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2021-06-01 | Abstract The main results of VTI’s investigations into low-emission combustors for gas-turbine units (GTU) are presented. In recent years, the combustion of a premixed fuel-air mixture (FAM) in a swirling flow in a limited space has been under development for this purpose to attain more complete combustion, stable fluctuation-free operation of a combustor in a wide range of parameters, and compliance with environmental protection requirements. To solve the problems encountered in this field, a procedure has been developed for assessing the effect of temperature in the combustion zone, flow velocity, combustor pressure, and other factors on the combustion stability. A review is presented of a comprehensive approach employed by VTI’s specialists to study the processes in combustors using numerical and experimental methods enabling them to cut down the cost and time of activities on development of low-emission combustors. For example, a relationship is presented between the numerically estimated quality of the produced fuel-air mixture and the experimental nitrogen oxide concentrations. A design parameter relating the process conditions in a flame tube with the vibration combustion amplitude is proposed. The experiments demonstrated a good correlation of the proposed parameter with measured pressure fluctuation amplitude. Of real interest are the presented examples of changes in the velocity and temperature fields with an increase in the working pressure, which should be considered in designing and bench testing the combustor. The low-emission combustors (LEC) developed for large- and medium-power GTUs are presented. The potential for scaling the combustors for other GTUs is examined. | Development of Low-Emission Combustors for Power-Generating GTUs | 10.1134/S0040601521060100 |
2021-06-01 | In this work, morphology and rheology of the blends of cyclic olefin copolymer (COC) with two types of crystalline polyolefins were investigated through a wide range of compositions. The used polyolefins had various plasticity, elasticity and viscoelastic behavior. Their molecular structures were similar but their molecular architectures were different in terms of comonomer content and composition distribution (i.e., a linear low-density polyethylene with 4 mol% of 1-butene comonomer (LLDPEB labeled as LLB) and nonuniform composition distribution and a polyolefin elastomer (POE) with 33 mol% of 1-butene comonomer and uniform composition distribution). Morphology of the COC/POE blends was droplet-matrix at low concentrations of the dispersed phase which was changed to co-continuous morphology at intermediate concentrations. Good compatibility and adhesion between phases were also observed. In COC/LLB blends, droplet-matrix morphology and good compatibility were observed between the two phases, except for compositions of 70/30 and 50/50, which exhibited continuous morphology and phase separation. The results of morphology and rheological data such as Cole–Cole plots and variations of viscosity versus composition revealed that these blends were immiscible. The interfacial interaction of the blend phases was investigated using rheological diagrams of variations of their complex viscosities, storage modulus versus frequency, relaxation time spectra and tan δ versus frequency. In addition, the interfacial tension was calculated using emulsion models. It was found that in the intermediate concentrations and COC-rich compounds, the interfacial interaction of the phases and form relaxation time of the dispersed particles of the COC/POE blends were higher than those of the COC/LLB blends, resulting in a further increase in elasticity. In blends with low COC content, the interfacial interaction of the phases and form relaxation time of the dispersed particles of the COC/LLB blends were higher than those of the COC/POE blends. | Effects of different molecular architectures in terms of comonomer content and composition distribution on the miscibility of cyclic olefin copolymer/polyolefin (COC/POE and COC/LLDPEB) blends | 10.1007/s13726-021-00914-z |
2021-06-01 | Abstract Oxidative conversion of methane to acetic acid at 150°С and a pressure of 6.5 MPa with the assistance of carbon monoxide on rhodium-modified ZSM-5 zeolites with different SiO 2 /Al 2 O 3 molar ratios was studied. A decrease in SiO 2 /Al 2 O 3 from 300 to 30 leads to a 2.7-fold increase in the acetic acid yield. Such behavior of the catalytic system correlates with an increase in the acidity, primarily with an increase in the density of Brønsted acid sites on the zeolite surface. Introduction of 0.1–0.5 wt % rhodium into the zeolite increases the acetic acid yield by a factor of more than 3. The highest acetic acid yield (0.53 mmol/g cat ) is attained on the zeolite with SiO 2 /Al 2 O 3 = 33 modified with 0.5 wt % Rh. The methane transformation to acetic acid occurs while involving both the acid sites of the zeolite and the sites formed by reactive rhodium particles. | Direct Low-Temperature Oxidative Conversion of Methane to Acetic
Acid on Rhodium-Modified Zeolites | 10.1134/S0965544121040058 |
2021-06-01 | In this study, intrinsic Ga 2 O 3 (i - Ga 2 O 3 ) film was deposited at about 80 K using a vapor cooling condensation system. Its bandgap energy was 5.0 eV. Low oxygen vacancy and defects were verified by using photoluminescence and Hall measurements. When a 40-nm-thick i - Ga 2 O 3 film was used as the gate dielectric layer of AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistors (MOS-HEMTs), threshold voltage, and gate breakdown voltage were − 3.5 V and − 538.0 V, respectively. The associated gate leakage current of the devices operating at a gate-source voltage of − 100 V was 0.57 μA. Furthermore, a saturation drain-source current of 186.2 mA/mm and a maximum extrinsic transconductance of 85.8 mS/mm were obtained for the devices operating at a gate-source voltage of 0 V and a drain-source voltage of 10 V. The unit gain cutoff frequency and the maximum oscillation frequency were 5.7 GHz and 11.0 GHz, respectively. The normalized noise and Hooge’s coefficient were 3.79 × 10 −14 Hz −1 and 5.06 × 10 −5 , respectively, when the devices operated at a frequency of 100 Hz, with a drain-source voltage of 1 V and a gate-source voltage of 5 V. | AlGaN/GaN Metal-Oxide-Semiconductor High-Electron Mobility Transistors Using Ga2O3 Gate Dielectric Layer Grown by Vapor Cooling Condensation System | 10.1007/s11664-021-08879-8 |
2021-06-01 | We present here a simple and robust photolithography method to fabricate high-porosity SU-8 negative resist templates using positive Poly(methyl methacrylate) (PMMA) as the porogenic agent. We report on how these nanoporous structures are greatly affected by the volume fraction of each component in the precursor solution and by the amount of exposure, to be limited to grant sufficient access to PMMA chains during pore formation. Tuning the porosity of the SU-8 film, we could broadly tailor its effective refractive index ( n ) from n = 1.27 to 1.58, in the visible/near-infrared domain. By further using the interference lithography technique, we demonstrated various kinds of porous micro/nanostructured surfaces. A hydrophobic effect was demonstrated with a high water contact angle of 130°. Such porous SU-8 templates could enhance, at modest cost, the design room of polymer-based photonic architectures in many areas, such as sensing, microfluidic and optoelectronic device. | Elaboration and characterization of nanoporous SU-8 template using PMMA as porogen | 10.1007/s10934-021-01036-w |
2021-06-01 | Low-density polyethylene (LDPE) containing oxygen scavenger based on sodium ascorbate (SA) nanoparticle (5%, 10%, and 15%) was produced by the extrusion method. The performance of produced films to prevent oxidation of packed peanuts during storage at 40 °C for a month was studied. Results indicated that greater SA released from active films into an aqueous food model. According to the results of ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) and DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate), higher antioxidant activity was observed in the aqueous simulant model than the ethanolic one. The images of the SEM (scanning electron microscopy) showed that the SA was often distributed in spherical particles and brighter spots in the LDPE matrix. The addition of the SA to the LDPE polymer matrix led to higher water vapor permeability, less uniformity, higher lightness and yellowness, and less tensile stress. Thermal degradation of SA in LDPE occurred in the range of 251 to 257 °C. The SA-LDPE active films efficiently retarded lipid oxidation in packed peanuts. | Characterization of Oxygen Scavenger Film Based on Sodium Ascorbate: Extending the Shelf Life of Peanuts | 10.1007/s11947-021-02631-0 |
2021-06-01 | A new theoretical solution is presented to determine the stress distribution in a ten-layer simply-supported circular composite plate subjected to the low-velocity impact. The aim of the current study is the investigation of the dynamic analysis of the composite plate when a cylindrical impactor hits the top layer of the plate with an initial velocity of 1 m/s. The plate is made of two adhesive layers adhere two aluminum layers to a six-layer carbon-epoxy laminated plate. The classical non-adhesive elastic contact theory and Hunter's relationship are used to simulate the contact behavior in terms of time and contact radius. By using Hamilton's principle and Layerwise theory, thirty-two equations of motion are derived. Moreover, Johnson–Cook’s criteria, the plastic simulation model, the normal stress–strain failure criterion theory were used for failure analysis of the aluminum, adhesive, and carbon-epoxy layers, respectively. The numerical method was used to solve the thirty-two differential equations of motion based on the finite difference method. Moreover, the relationship between stress and strain is re-written in the numerical code so that the failure criterion theories are satisfied. Moreover, according to the defined failure criterion for each layer, the damage is checked at the end of every time step. In addition, the damping behavior of the composite plate after applying the contact pressure caused by the impact was also investigated. The results showed that the impact resulted in residual stress in the plate. | Dynamic damage analysis of a ten-layer circular composite plate subjected to low-velocity impact | 10.1007/s43452-021-00238-y |
2021-06-01 | Tribological characteristics of low carbon steel (LCS) have been investigated on as-received coarse grains of 67 μm size and ultrafine-grained (UFG) microstructure of 0.2 μm size, which was prepared by equal-channel angular pressing (ECAP). Two-body abrasion tests have been carried out against silicon carbide abrasive papers at various loads. Furthermore, solid particle (silica sand) erosion tests were also conducted at normal particle impingement angles at various impact velocities. The ECAP process improved the resistance to abrasive and erosion wear of UFG LCS as compared to that of as-received coarse-grained steel. The abrasive and erosion wear resistances of UFG LCS were improved under severe conditions. The abrasive wear mechanism of as-received coarse-grained LCS was governed by micro-cutting, whereas it was microploughing in UFG LCS. The mechanism of material removal in erosive wear was brittle in as-received material in contrast to ductile in UFG steel. | Effect of Grain Refinement on Tribological Study of Low Carbon Steel | 10.1007/s12666-021-02242-5 |
2021-06-01 | Root lengthening is regarded as a strategy for rice to adapt to the low phosphorus level. Namely, by increasing the length and surface area of root, rice has an opportunity to enhance its phosphorus adsorption efficiency under low phosphorus conditions. The relationship between main root lengthening of rice seedlings under low phosphorus conditions with the endogenous hormone contents and expression of expansin genes were examined by using methods of the hormone content determination and transcriptome sequencing. The experimental results suggested that after low phosphorus treatment for 15 days, the main root length of Tongjing981 (TJ981) and Zhendao99 (ZD99) was considerably longer than that of the control. However, the main root length of Zhenghan6 (ZH6) was shorter compared to the control. It reveals that the main root length of different rice varieties had different response modes to low phosphorus treatment. After low phosphorus treatment, the IAA content of TJ981 and ZD99 had dramatically increased IAA contents compared to the control, while the IAA content in the root system of ZH6 evidently decreased compared to the control. This finding indicates that the response mode of the IAA content in the roots of three rice varieties for the test to low phosphorus treatment was consistent with that of the main root length. Meanwhile, low-concentrated (5 mg L −1 ) exogenous IAA markedly elongated the main root of TJ981. Consequently, a higher IAA content in rice roots than that of the control may result in lengthening the rice main root induced by low phosphorus treatment. Low phosphorus treatment induced the expression of multiple expansin genes in TJ981 and ZD99 roots; meanwhile, exogenous IAA treatment at various doses also promoted the expression of expansin genes. Hence, the expression of expansin genes in rice roots induced by low phosphorus treatment was related to the increased IAA content caused by low phosphorus stress. Moreover, low phosphorus treatment promoted the length of cells in the elongation zone of TJ981 compared with the control. | Mechanism of Low Phosphorus Inducing the Main Root Lengthening of Rice | 10.1007/s00344-020-10161-w |
2021-06-01 | We report results from a one-dimensional, numerical simulation of a capacitively coupled $$He/O_2$$ H e / O 2 admixture plasma, operated at pressure varying from 1.5 to 7.5 Torr and over a range of molecular oxygen admixtures ( $$He+0.1\%O_2$$ H e + 0.1 % O 2 – $$He+10\%O_2$$ H e + 10 % O 2 ). This study is used to investigate the effect of the gas pressure and the addition of small fractions of molecular oxygen on some important species production which have been extensively used for various biomedical applications and several new plasma technologies. The species densities have been presented, and the dominant key production processes have been identified. At a fixed ( $$He+1\%O_2$$ H e + 1 % O 2 ) admixture, the electron density decreases with increasing pressure, and the densities of negative ions are relatively high at high pressures and decrease for the positive ions. However, the atomic O , the molecular metastable $$O_2(v)$$ O 2 ( v ) , singlet-delta $$O_{2}(a ^{1}\mathrm {\Delta _{g}})$$ O 2 ( a 1 Δ g ) and singlet-sigma $$O_{2}(b ^{1}\mathrm {\Sigma _{g}^{+}})$$ O 2 ( b 1 Σ g + ) states are found to be the dominant species and their densities are weakly dependent on the gas pressure. At a fixed pressure, as the $$O_2$$ O 2 admixture increases, the electron impact with $$O_2$$ O 2 molecules becomes higher, and consequently, the electron generation decreases considerably. The formation of O , $$O_2(v)$$ O 2 ( v ) , $$O_{2}(a ^{1}\mathrm {\Delta _{g}})$$ O 2 ( a 1 Δ g ) and $$O_{2}(a ^{1}\mathrm {\Delta _{g}})$$ O 2 ( a 1 Δ g ) increases until it reaches a peak at $$4\%O_2$$ 4 % O 2 and then falls significantly with increasing $$O_2$$ O 2 admixture. However, the atomic metastable $$O(^{1}\mathrm {D})$$ O ( 1 D ) and $$He^*$$ H e ∗ are less important and they decrease rapidly due to collisional quenching or Penning ionization. The ozone $$O_3$$ O 3 formation is optimal at $$4\%O_2$$ 4 % O 2 . The positive and negative atomic and molecular ions are also relatively less important, and they decrease sharply with increasing $$O_2$$ O 2 admixture due to ion-ion and ion-molecule neutralization. The addition of oxygen resulted in a decrease in all plasma species due to the electronegativity property of oxygen. These results are in fairly good agreement with some experimental observations and allow for a better understanding of the main physicochemical mechanisms taking place in $$He/O_2$$ H e / O 2 plasmas admixtures. | Numerical Investigation of Reactive Species Generation in
$$He/O_2$$
H
e
/
O
2
Admixture Capacitively Coupled Plasma | 10.1007/s13369-020-04955-z |
2021-06-01 | Abstract The reactions of lead bromide with 7,7,8,8-tetracyanoquinodimethane and anthracen-9-ylmethanamine hydrobromide in dimethylformamide (DMF) afford the known low-dimensional perovskite {PbBr 2 (DMF)} n ( I ) with an impurity of a new hybrid 1D perovskite {Ca(DMF) 6 [PbBr 3 ] 2 } n ( II ), which is isolated in the individual form and characterized by X-ray diffraction analysis. In the crystal of compound II , lead bromide forms infinite chains of PbBr 5 octahedra with one vacant vertex between which calcium cations coordinated by the DMF molecules are arranged. The calcium cations presumably have got into the reaction mixture from water used for the washing of the reaction vessel for crystallization after the previous attempt of the synthesis. An attempt of the purposeful preparation of this hybrid 1D perovskite from various calcium salts as sources of this metal ion gives one more new low-dimensional perovskite {Ca(DMF) 6 [PbBr 2.3 Cl 0.7 ] 2 } n ( III ) in which halide anions (bromide and chloride anions from lead bromide and calcium chloride, respectively) build up the coordination sphere of the lead ion to an octahedral one inducing no noticeable changes in the crystal packing compared to that of compound II . The X-ray diffraction results are deposited with the Cambridge Crystallographic Data Centre (CIF files CCDC nos. 2045586 ( I ), 2047219 ( II ), and 2047220 ( III )). | New Low-Dimensional Perovskites Based on Lead Bromide | 10.1134/S1070328421060026 |
2021-06-01 | We investigated sputtered nanocarbon films with respect to the effect of suppressing surface oxygen on their electrochemical properties. The nanocarbon film consisted of nanocrystallites with mixed sp 2 and sp 3 bonds formed by unbalanced magnetron sputtering. Ultraviolet/ozone (UV/O 3 ) irradiation and electrochemical pretreatment (ECP) were conducted to change the surface oxygen concentration of nanocarbon film. X-ray photoelectron spectroscopy (XPS) measurements revealed that nanocarbon films with different amounts of surface oxygen could be prepared. In addition, we observed no significant increase of the surface roughness ( R a ) at the angstrom level after treatments, owing to a stable structure containing 40% of sp 3 bonds. The electrode characteristics, including the potential window and electrochemical properties for some redox species, such as Ru(NH 3 ) 6 3+/2+ , were investigated. Some electrochemical measurements of zinc ions (Zn 2+ ) and hydrogen peroxide (H 2 O 2 ) showed that the electrochemical reaction was improved by suppressing the surface oxygen. These results clearly indicated that the low surface oxygen concentration plays an important role in these electrochemical reactions. | Suppression of Surface Oxygen on Nanocarbon Film Electrodes for Maintaining Electrode Activity | 10.2116/analsci.20P315 |
2021-06-01 | An ultra-energy-efficient interconnect structure based on multilayer graphene nanoribbon (MLGNR) interconnects for deep-nanometer technologies is proposed herein. First, a low-swing interconnect based on MLGNRs and high-performance interface circuits using carbon nanotube field-effect transistors (CNTFETs) is proposed. Then, an ultra-energy-efficient interconnect structure is obtained by actively shielding such low-swing lines. The structures under study are simulated comprehensively at the 7-nm technology node. The results indicate that the MLGNR interconnect is significantly more energy efficient than its multiwall carbon nanotube (MWCNT) counterpart in the low-voltage regime. Moreover, the proposed approach is superior to its MLGNR counterparts. The proposed structure leads to 86%, 75%, and 31% lower energy consumption over a length of 500 µm as compared with the typical, actively shielded, and low-swing MLGNR interconnects, respectively. Moreover, the impact of the ratio of the widths of the signal line to the shield line on the performance of the interconnects is evaluated. The energy consumption reduction achieved by the proposed approach is mostly preserved even when using minimum-width shield lines on wider signal lines to reduce the area overhead. Moreover, the impact of process variations on the performance of the interconnects is assessed using Monte Carlo simulations, demonstrating the robustness of the proposed approach. | An ultra-energy-efficient crosstalk-immune interconnect architecture based on multilayer graphene nanoribbons for deep-nanometer technologies | 10.1007/s10825-021-01677-9 |
2021-06-01 | In the last decade, the Kepler and CoRoT space-photometry missions have demonstrated the potential of asteroseismology as a novel, versatile and powerful tool to perform exquisite tests of stellar physics, and to enable precise and accurate characterisations of stellar properties, with impact on both exoplanetary and Galactic astrophysics. Based on our improved understanding of the strengths and limitations of such a tool, we argue for a new small/medium space mission dedicated to gathering high-precision, high-cadence, long photometric series in dense stellar fields. Such a mission will lead to breakthroughs in stellar astrophysics, especially in the metal poor regime, will elucidate the evolution and formation of open and globular clusters, and aid our understanding of the assembly history and chemodynamics of the Milky Way’s bulge and a few nearby dwarf galaxies. | HAYDN | 10.1007/s10686-021-09711-1 |
2021-06-01 | Abstract Corrosion of low-carbon steel corrosion in 2.0 M H 2 SO 4 and 2.0 M H 3 PO 4 containing Fe(III) salts is studied using the mass loss of metal specimens and voltammetric measurements on a rotating disk electrode. It is established that during steel corrosion in mineral acid solutions containing Fe(III) salts, the anodic ionization of metallic iron proceeds in the kinetic region. The cathodic reaction combines the parallel and independent processes of the kinetically controlled hydrogen evolution and the diffusion-controlled reduction of Fe(III) cations to Fe(II). The potentiometry and cyclic voltammetry on a platinum electrode in acid solutions containing Fe(III) salts shows that Fe(III) cations in these media are bound into complexes with acid anions. The stronger the complexes formed by Fe(III) cations, the lower their oxidation potential and diffusion coefficient. The drop in the diffusion coefficient of Fe(III) cations in mineral acid solutions affects the rate of their diffusion-controlled reduction on steel. Introducing FePO 4 into a H 3 PO 4 solution accelerates corrosion of low-carbon steel less than an equimolar Fe 2 (SO 4 ) 3 additive in a H 2 SO 4 solution. The effect is a result of the lower diffusion coefficient of Fe(III) cations in a H 3 PO 4 solution, relative to a H 2 SO 4 solution. | Characteristics of the Mechanism of Corrosion of Low-Carbon Steels in Acid Solutions Containing Fe(III) Salts | 10.1134/S0036024421060029 |
2021-06-01 | This study aimed to evaluate the effect of photobiomodulation (PBM) for prevention of radiodermatitis in an irradiated mouse model and compare the efficacy of PBM using 633- or 830-nm wavelengths. Irradiated mice were randomly distributed into three groups: A (633 nm), B (830 nm), and C (without PBM). On post-irradiation days 7 and 21, we compared acute damage and recovery in treated skin samples to non-irradiated skin using H&E, Masson’s trichrome, anti-CD45 and PCNA immunohistochemistry, and a TUNEL assay. Grade 3 radiodermatitis was evident only in group C. Compared with that in group C, the skin in groups A and B had significantly less epidermal hyperplasia, inflammatory cell infiltration, and thinner dermis on day 7 and less inflammatory cell infiltration, fewer apoptotic cells, and thinner dermis on day 21. However, there was no significant difference between groups A and B. This study indicates PBM could prevent severe radiodermatitis by reducing epidermal and dermal damage, inflammation, and apoptosis. There was no difference in PBM efficacy between the 633- and 830-nm wavelengths. | Effect of photobiomodulation therapy on radiodermatitis in a mouse model: an experimental animal study | 10.1007/s10103-020-03123-x |
2021-06-01 | Abstract The article is devoted to the study of the hydrodynamics of an ejection jet flow. The basic geometric parameters of a free turbulent jet are described. The authors proposed a cellular model of ejection, which allows one to determine with high accuracy the velocity of the gas and solid phases at any point in the space of the jet. The trajectory of the flight of the solid phase inside a turbulent gas jet is described. Particular attention in calculating the velocity of the solid phase is given to determining the drag coefficient of the particle assembly. An analysis was performed showing the dependence of the amount of ejected solid phase from the fluidized bed on the diameter of the nozzle. | Determination of Velocity and Concentration of Particles of a Solid Phase in a Turbulent Gas Jet, Immersed in a Fluidized Bed | 10.1134/S1070363221060323 |
2021-06-01 | Background and aim Epichloë gansuensis increases the tolerance of host plants to abiotic stress. However, little is known about the mechanism by which E. gansuensis improves grass growth under low nitrogen availability stress. Methods Achnatherum inebrians with E. gansuensis (E+) and without E. gansuensis (E-) were treated with modified 1/2 Hoagland containing 0.01 mM (low N) or 7.5 mM N (normal level) for 18 weeks. After 18 weeks of treatment with N, the dry weight of E+ and E- plants were measured, and the metabolomics analysis of leaves and roots grown under two different N concentrations was conducted with GS-MS to determine differential metabolites and metabolic pathways. Result E+ A. inebrians had higher dry weight of leaves and roots compared to the E- A. inebrians under low N stress. E. gansuensis increased the tolerance of A. inebrians to low N stress by its capability to increase the content of organic acids (salicylic acid and 3-hydroxypropionic acid) and glucose-6-phosphate in leaves, and E. gansuensis increased the content of fatty acids (linolenic acid and oleic acid) and amino acids (glycine and 4-aminobutyric acid) in roots under low N stress. Finally, E. gansuensis reprogramed the metabolic pathway of amino acids of host grasses to adapt to the different N concentration. Conclusion Our results reveal the chemical mechanism by which E. gansuensis enhances the tolerance of host grasses to low N, and provide the theoretical basis for utilizing E. gansuensis , improving of grasses and crops, and for developing new germplasm for low-N tolerant grasses. | Metabolomics insights into the mechanism by which Epichloë gansuensis endophyte increased Achnatherum inebrians tolerance to low nitrogen stress | 10.1007/s11104-021-04930-z |
2021-06-01 | Glycocalyx (GCX) is a thin layer of negatively charged glycoproteins that covers the vascular endothelial surface and regulates various biological processes. Because of the delicate and fragile properties of this structure, it is difficult to detect GCX morphologically. We established a simple method for a three-dimensional visualization of endothelial GCX using low-vacuum scanning electron microscopy (LVSEM) on formalin-fixed paraffin-embedded (FFPE) sections. Mouse kidney tissue was fixed with 10% buffered formalin containing 1% Alcian blue (ALB) via perfusion and immersion. FFPE sections were observed by light microscopy (LM) and LVSEM, and formalin-fixed epoxy resin-embedded ultrathin sections were observed by transmission electron microscopy (TEM). The endothelial GCX from various levels of kidney blood vessels was stained blue in LM and confirmed as a thin osmiophilic layer in TEM. In LVSEM, the sections stained by periodic acid methenamine silver (PAM) revealed the endothelial GCX as a layer of dense silver-enhanced particles, in both the samples fixed via perfusion and immersion. Correlative light and electron microscopy (CLEM) revealed the fine visible structure of endothelial GCX. This simple method using FFPE samples with ALB will enable the three-dimensional evaluation of endothelial GCX alterations in various human diseases associated with endothelial injury in future studies. | Three-dimensional electron microscopy for endothelial glycocalyx observation using Alcian blue with silver enhancement | 10.1007/s00795-020-00267-1 |
2021-06-01 | The ultra-low permeability reservoir is regarded as an important energy source for oil and gas resource development and is attracting more and more attention. In this work, the active silica nanofluids were prepared by modified active silica nanoparticles and surfactant BSSB-12. The dispersion stability tests showed that the hydraulic radius of nanofluids was 58.59 nm and the zeta potential was − 48.39 mV. The active nanofluids can simultaneously regulate liquid–liquid interface and solid–liquid interface. The nanofluids can reduce the oil/water interfacial tension (IFT) from 23.5 to 6.7 mN/m, and the oil/water/solid contact angle was altered from 42° to 145°. The spontaneous imbibition tests showed that the oil recovery of 0.1 wt% active nanofluids was 20.5% and 8.5% higher than that of 3 wt% NaCl solution and 0.1 wt% BSSB-12 solution. Finally, the effects of nanofluids on dynamic contact angle, dynamic interfacial tension and moduli were studied from the adsorption behavior of nanofluids at solid–liquid and liquid–liquid interface. The oil detaching and transporting are completed by synergistic effect of wettability alteration and interfacial tension reduction. The findings of this study can help in better understanding of active nanofluids for EOR in ultra-low permeability reservoirs. | Mechanism of active silica nanofluids based on interface-regulated effect during spontaneous imbibition | 10.1007/s12182-020-00537-8 |
2021-06-01 | Phosphorus (P) is an essential macronutrient to all crops including rice and it plays a key role in various plant activities and development. Low availability of P in the soils negatively, influences rice crop growth and causes significant yield loss. In the present study, we characterized a set of 56 germplasm lines for their tolerance to low soil P by screening them at low soil P and optimum soil P levels along with low soil P tolerant and sensitive check varieties. These lines were genotyped for the presence/absence of tolerant allele with respect to the major low soil P tolerance QTL, Pup1 , using a set of locus specific PCR-based markers, viz., K46-1, K46-2, K52 and K46CG-1. High genetic variability was observed for various traits associated with low soil P tolerance. The yield parameters from normal and low soil P conditions were used to calculate stress tolerance indices and classify the genotypes according to their tolerance level. Out of the total germplasm lines screened, 15 lines were found to be tolerant to low soil P condition based on the yield reduction in comparison to the tolerant check, but most of them harbored the complete or partial Pup1 locus. Interestingly, two tolerant germplasm lines, IC216831 and IC216903 were observed to be completely devoid of Pup1 and hence they can be explored for new loci underlying low soil P tolerance. | Morphological and molecular screening of rice germplasm lines for low soil P tolerance | 10.1007/s13562-020-00586-5 |
2021-06-01 | Objective NLRP3 inflammasome may play a key role in OA pathogenesis. Stromal cell-derived factor-1 (SDF-1) is a homeostatic CXC chemokine. Since the role of SDF-1 in OA has not been explored, this study aimed to examine the effect of SDF-1 on NLRP3 inflammasome and pyroptosis in synoviocytes from OA joints. Materials and methods Human synovium was obtained from OA patients for isolation of primary synoviocytes and a murine model of collagenase-induced OA was established for testing intra-articular injections of SDF-1. Immunoblotting assays were used to examine the effects and underlying mechanism of action of SDF-1 on NLRP3 inflammasome and synoviocyte pyroptosis in synoviocytes. Inhibitors of AMPK and PI3K–mTOR were utilized to investigate the key signaling pathways involved in SDF-1-mediated OA inflammasome formation and pyroptosis. Results Synoviocytes from OA joints exhibited significantly higher expression of NLRP3 inflammasome and biomarkers of synoviocyte pyroptosis relative to healthy individuals. This was confirmed in the collagenase-induced OA model, where OA synoviocytes had a significantly lower SDF-1 expression than healthy ones. SDF-1 treatment in synoviocytes of OA patients and collagenase-induced OA led to significant downregulation in the expression of NLRP3 inflammasome and synoviocyte pyroptosis biomarkers. Inhibition of the AMPK signaling pathway significantly suppressed the inhibitory effect of SDF-1 on NLRP3 inflammasome expression of OA synoviocytes. However, blocking the SDF-1-activated PI3K–mTOR signaling pathway could still suppress the expression of NLRP3 inflammasome and synoviocyte pyroptosis biomarkers. Conclusions SDF-1 ameliorates NLRP3 inflammasome and pyroptosis in OA synoviocytes through activation of the AMPK signaling pathway. Therefore, SDF-1 may be a novel therapeutic target for OA. | Exogenous stromal cell-derived factor-1 (SDF-1) suppresses the NLRP3 inflammasome and inhibits pyroptosis in synoviocytes from osteoarthritic joints via activation of the AMPK signaling pathway | 10.1007/s10787-021-00814-x |
2021-06-01 | As the calculation of transformer no-load characteristics measured by low-frequency test method is not perfect, different interpolation methods are explored to fit and convert the transformer's volt-ampere characteristics under power frequency (50 Hz) excitation to find the best interpolation fitting conversion method. The no-load test of transformer is carried out by using 10 Hz, 15 Hz, 20 Hz low-frequency square wave and triangular wave excitation. Then the measured excitation voltage, excitation current and no-load loss are converted to those of 50 Hz sine wave excitation. The converted volt-ampere characteristic curve is calculated by the proposed algorithm, and compared with the measured results under the 50 Hz sine wave excitation. Experiments show that under the condition that the magnetic flux amplitudes are equal at each frequency of non-sinusoidal and sine waves, whether it is square wave or triangular wave excitation, the volt-ampere characteristic curve converted to the 50 Hz sine wave excitation by the proposed method can better approximate the curve of the measured 50 Hz sine wave excitation. The average values of the relative errors of the converted excitation current of the three frequencies are within 4%, and those of the converted excitation voltage of the square wave are within 1.1%, and those of the converted excitation voltage of the triangular wave are within 0.47%. Compared with the generalized Steinmetz equation method and the multi-frequency method, the proposed method has a better conversion effect and can almost replace the no-load test results of the 50 Hz sine wave, which has practical value in engineering. | Comparison of low-frequency non-sinusoidal measurement for transformer no-load characteristics based on different interpolation methods | 10.1007/s00202-020-01199-w |
2021-06-01 | The effect of glutarimide dioxime (H 3 A) on the fate of Tc in aqueous solution was studied, the results found that the distribution ratio of Tc between TBP and aqueous phase decreased by one order of magnitude with addition of H 3 A, due to the formation of low-valent Tc complexes with H 3 A. Further study of coordination mode between low-valent Tc and H 3 A was carried by using Re as substitute. Firstly, the low-valent Re complexes with H 3 A were prepared by reduction of Re(VII) using hydrazine in the presence of H 3 A, the results showed that pH 8.0, high C H3A and high C hydrazine are favorable for the formation of low-valent Re complexes, with a characteristic peak at 380 nm. Subsequently, the species of low-valent Re complexes were further studied by XPS, ESI–MS and EXAFS, low-valent Re is tetravalent and forms 1:1 (ReA) and 1:2 (ReA 2 ) mononuclear complexes with H 3 A. The low-valent Re/Tc complexes are air-stable in aqueous solution. | The coordination of low-valent Re/Tc with glutarimide dioxime and the fate of Tc in aqueous solution: spectroscopy, ESI–MS and EXAFS | 10.1007/s10967-021-07738-4 |
2021-06-01 | The current T-stub specimen of welded beam-to-column connections in steel structures was improved by adding clamping ends at both sides for convenience of fatigue tests. Uniaxial fatigue tests of the T-stub specimens were conducted. The fatigue properties and failure characteristics of the T-stub specimens were summarized and compared with those of two other standard welded joint configurations. Based on finite element analysis, various fatigue assessment approaches were used to predict the fatigue life of the specimens and the assessment results were compared with the test results. Previously developed unified design curves suitable to high-cycle and low-cycle fatigue assessment of standard welded joint configurations were extended to welded joints in beam-to-column connections. The results show that accurate experimental results can be obtained using the improved T-stub specimens with clamping ends; Under cyclic loading, the welded joint in beam-to-column connections has satisfying energy dissipation capacity, but the fatigue strength is relatively poor; the unified design curves are well applicable to the fatigue life assessment and design of welded beam-to-column connections in steel structures. | Fatigue Test Research on Improved T-Stub Specimen of Welded Beam-to-Column Connections | 10.1007/s11668-021-01118-6 |
2021-06-01 | Sustainable urban drainage systems are multi-functional nature-based solutions that can facilitate flood management in urban catchments while improving stormwater runoff quality. Traditionally, the evaluation of the performance of sustainable drainage infrastructure has been limited to a narrow set of design objectives to simplify their implementation and decision-making process. In this study, the spatial design of sustainable urban drainage systems is optimized considering five objective functions, including minimization of flood volume, flood duration, average peak runoff, total suspended solids, and capital cost. This allows selecting an ensemble of admissible portfolios that best trade-off capital costs and the other important urban drainage services. The impact of the average surface slope of the urban catchment on the optimal design solutions is discussed in terms of spatial distribution of sustainable drainage types. Results show that different subcatchment slopes result in non-uniform distributional designs of sustainable urban drainage systems, with higher capital costs and larger surface areas of green assets associated with steeper slopes. This has two implications. First, urban areas with different surface slopes should not have a one-size-fits-all design policy. Second, spatial equality must be taken into account when applying optimization models to urban subcatchments with different surface slopes to avoid unequal distribution of environmental and human health co-benefits associated with green drainage infrastructure. | Many-Objective Optimization of Sustainable Drainage Systems in Urban Areas with Different Surface Slopes | 10.1007/s11269-021-02840-4 |
2021-06-01 | Abstract The SiCOH low- k dielectric film was grown on Si substrate using plasma-enhanced chemical vapor deposition method. Atomic structure and optical properties of the film were studied with the use of X‑ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) absorption spectroscopy, Raman spectroscopy, and ellipsometry. Analysis of XPS data showed that the low- k dielectric film consists of Si–O 4 bonds (83%) and Si–SiO 3 bonds (17%). In FTIR spectra some red-shift of Si–O–Si valence (stretching) vibration mode frequency was observed in the low- k dielectric film compared with the frequency of this mode in thermally grown SiO 2 film. The peaks related to absorbance by C–H bonds were observed in FTIR spectrum. According to Raman spectroscopy data, the film contained local Si–Si bonds and also C‒C bonds in the s–p 3 and s–p 2 hybridized forms. Scanning laser ellipsometry data show that the film is quite homogeneous, homogeneity of thickness is ~2.5%, and homogeneity of refractive index is ~2%. According to the analysis of spectral ellipsometry data, the film is porous (porosity is about 24%) and contains clusters of amorphous carbon (~7%). | Atomic Structure and Optical Properties of Plasma Enhanced Chemical Vapor Deposited SiCOH Low-k Dielectric Film | 10.1134/S0030400X21050088 |
2021-06-01 | The age of the Silurian Lower Red Beds in the Upper Yangtze region remains debatable. Twenty-four samples were collected for conodont biostratigraphical studies from the Paiyunan Formation in the Sanbaiti Section, Huaying, Sichuan Province. The conodont fauna from the Paiyunan Formation, together with the graptolites from the underlying Lungmachi Formation, indicates that the Lower Red Beds at Sanbaiti correspond to the lower Telychian. Comparative analysis indicates that most exposures of the Lower Red Beds in the Upper Yangtze region can be assigned, in general, to the Telychian Stage, except for several localities, where the Lower Red Beds can be roughly dated as an interval between the upper Aeronian and lower Telychian. | Age of the Silurian Lower Red Beds in South China: Stratigraphical Evidence from the Sanbaiti Section | 10.1007/s12583-020-1350-6 |
2021-06-01 | Purpose 5-iododeoxyuridine (IUdR), a radiosensitizer able to be incorporated into nascent DNA during synthesis, makes the DNA easy to break upon irradiation. IUdR has been used together with low energy radiation in cancer treatments mechanistically by Auger electron induction to damage DNA. In this study, a small-sized transmission X-ray tube equipped with a Lanthalum target (La-tX ray) generating 33–40 keV-enriched photons was used in combination with IUdR for Auger cancer therapy, and the performance was evaluated by multiple assays in vitro and in vivo. Methods Cytotoxicity, thymidine replacement and nuclear incorporation of IUdR were evaluated in NG4TL4 fibrosarcoma cells and SAS head and neck cancer cells. After treatment of IUdR + La-tX ray irradiation or IUdR + Co-60 irradiation, cell survival and DNA damages were evaluated by colony forming assay and comet assay/γH2AX staining, respectively. Growth of tumor xenografts receiving an intratumoral IUdR injection (45 μg) and/or La-tX ray irradiation were measured. Results For NG4TL4 and SAS cells, the IC50 of IUdR were ~ 7 and ~ 10 μg/ml, respectively. As compared to IUdR + Co-60 irradiation, IUdR + La-tX ray resulted in higher DNA breaks in cancer cells. Also, IUdR + La-tX ray resulted in higher cell toxicity than IUdR + Co-60. In the in vivo study, tumor xenografts showed inhibited growth in the IUdR + La-tX ray treatment, compared to those in the IUdR or La-tX ray treatment alone. Conclusion This study demonstrated the potential of cancer Auger electron therapy using a small-sized transmission X ray tube that generated enriched specific energy X rays for Auger electron induction. | Enhancement of IUdR Radiosensitization in Cancer Therapy by Low-Energy Transmission X Ray Irradiation | 10.1007/s40846-021-00616-0 |
2021-06-01 | Purpose Based on findings of the Asian low-concentration atropine for myopia progression study, a concentration of 0.05% has been proposed as a good compromise between safety and efficacy for myopia control. However, no data on side effects have been published so far in Caucasian children receiving this dose. Methods Prior to commencement of bilateral atropine treatment with 0.05% atropine, 19 myopic children aged 5 to 15 years were treated in only one eye at bedtime leaving the other eye as a control. Pupil size, accommodation amplitude and near visual acuity were measured at 10:00 a.m. the next day and compared to the untreated contralateral control eye. The results were then compared to a cohort of 18 children whose treatment with 0.01% atropine commenced in a similar fashion. Results Twelve children (63%) reported visual impairment or reading difficulties. Anisocoria was 2.9 ± 1.1 mm. In comparison, 0.01% atropine led to a significantly less anisocoria of 0.8 ± 0.7 mm ( p < 0.0001). Accommodation was decreased by − 4.2 ± 3.8 D in 0.05% atropine treated eyes, whereas 0.01% atropine induced hypoaccommodation of − 0.05 ± 2.5 D ( p < 0.01). Near visual acuity was not significantly reduced in eyes treated with 0.05% atropine compared to 0.01% atropine ( p = 0.26). Conclusion Compared to 0.01%, our data indicate stronger more relevant side effects of 0.05% topical atropine in young Caucasian children with progressive myopia as recently reported in Asian children, potentially compromising acceptance and compliance. | Side effects of topical atropine 0.05% compared to 0.01% for myopia control in German school children: a pilot study | 10.1007/s10792-021-01755-8 |
2021-06-01 | Environmental degradation has severely affected the natural cycle of ecosystem. It’s high time now and humans should execute strategies effectively to protect the further degradation. Initially, we need to understand the ways that might affect the environment. Thus, existing research is designed to explore the nonlinear association between financial development (FD) and carbon dioxide emissions (CO2) in the context of low-income countries by employing the yearly data of 1990–2016. The panel smooth transition regression model (PSTR) is applied, and the result confirmed that the nexus between the two variables are nonlinear. Moreover, it also shows that at a low regime, FD increases the CO2 emissions but as the economy of low-income states progress to the high regime, the association between the two variables becomes negative and significant. The study also confirms that FD can reduce CO2 emissions once it reaches a certain threshold point. Based on these findings, new insights are provided for the policymakers, and several policies are suggested to improve the environmental quality in low-income countries. | Financial development, international trade, and environmental degradation: a nonlinear threshold model based on panel smooth transition regression | 10.1007/s11356-020-11912-8 |
2021-06-01 | Identification of “donors” possessing superior traits to adapt to low phosphorus (P) soils is a primary requirement to develop efficient crop plants for sustainable agricultural production. Diverse wheat ( Triticum aestivum L., 89) and triticale (× Triticosecale Wittmack, 15) genotypes were phenotyped in soil with low and sufficient P for two seasons and once in the hydroponic system. Principal component analysis of relative biomass and grain weight revealed four clusters each for wheat and triticale. In low P soil, genotypes in the efficient cluster showed lesser reduction in total biomass, grain weight, total P uptake, and harvest index (HI), and improved P acquisition efficiency (PAE) and P harvest index (PHI) as compared to the inefficient cluster. In hydroponics, reduction in total biomass was less while root biomass and PAE increased at low P in the efficient genotypes. Out of 22 (soil) and 38 (hydroponics) P-efficient wheat genotypes, nine were overlapping in both screens while in P-inefficient cluster, out of 23 (soil) and 5 (hydroponics), three were common. A few P-efficient genotypes identified were DL784-3, DBW 16, and GW 322 and triticale TREAT, whereas P inefficient were C306 and ABACUS PVR (triticale). The selections in hydroponics are likely to be relevant in the field as demonstrated by overlapping of genotypes in both the mediums. Genotypic variations in P efficiency were strongly associated with P utilization rather than P uptake. | Evaluation of Diverse Wheat (Triticum aestivum) and Triticale (× Triticosecale) Genotypes for Low Phosphorus Stress Tolerance in Soil and Hydroponic Conditions | 10.1007/s42729-021-00436-w |
2021-06-01 | Purpose of the Review Surgical site infections (SSI) affect millions of individuals around the world, leading to a significant burden on perioperative morbidity and healthcare economy. Over the past decade low-income and middle-income countries (LMICs) have made substantial advancements on infection prevention strategies. However, the incidence of SSI is still increasing in many LMICs across all surgical specialties, denoting overlooked areas and ongoing challenges. This article aims to describe the role of anesthesiologists on current standards of infection prevention and sterility as well as ongoing developments in resource-limited settings, with a focus on LMICs. Recent Findings Recent estimates indicate a threefold increase in the incidence of SSI across LMICs over the past two decades, approaching two times the estimated SSI incidence of high-income countries. As a result, public health officials have promoted standard practices for infection prevention in the surgical arena by creating multidisciplinary teams and tailoring to the availability of equipment and resources. Anesthesiologists play a pivotal role for the implementation of infection prevention strategies such as antimicrobial prophylaxis, normothermia, intraoperative glucose control, and adequate handling of intravenous anesthetics. Unfortunately, the lack of cohesive practices and leadership structures, along with poor surveillance systems, are still common barriers. One potential method of overcoming these obstacles is investment in sustainable national infection prevention programs. Summary Infection prevention standards should be tailored to local workflow and institutional resources. The successful implementation of programs in LMICs depends on sustainable national infection prevention programs which includes a well-trained team and an institutional climate of safety. | Sterility and Infection Prevention Standards for Anesthesiologists in LMICs: Preventing Infections and Antimicrobial Resistance | 10.1007/s40140-021-00441-w |
2021-06-01 | Trigeminal neuralgia is a recurrent episode of facial pain, that may be associated with other conditions such as multiple sclerosis, neoplasms, and nerve compromises or may occur due to an unknown cause. The available treatments are pharmacotherapy or surgery; however, both are susceptible to develop side effects. Photobiomodulation could be a promising alternative therapy for trigeminal neuralgia. A systematic review of literature was carried out using the PRISMA protocol, in the PubMed/MEDLINE, Embase, and Web of Science databases. Risk of bias by ROB 2.0 protocol was performed in included studies. Initially, 20 identified articles were collected varying between the years of 1983–2018, from which 6 were included. A total of 193 patients were evaluated; photobiomodulation was compared to conventional therapies, TENS, and therapy combinations with pharmacotherapy. The overall risk of bias was low, with some concerns in the randomization and double-blinding process; moreover, there are few reports in the literature. Photobiomodulation appears to be as effective as conventional therapies, being a coadjutant therapeutic opportunity for the treatment of trigeminal neuralgia. | Photobiomodulation on trigeminal neuralgia: systematic review | 10.1007/s10103-020-03198-6 |
2021-06-01 | Purpose of the Review Chronic low back pain (CLBP) is a major contributor to societal disease burden and years lived with disability. Nonspecific low back pain (LBP) is attributed to physical and psychosocial factors, including lifestyle factors, obesity, and depression. Mechanical low back pain occurs related to repeated trauma to or overuse of the spine, intervertebral disks, and surrounding tissues. This causes disc herniation, vertebral compression fractures, lumbar spondylosis, spondylolisthesis, and lumbosacral muscle strain. Recent Findings A systematic review of relevant literature was conducted. CENTRAL, MEDLINE, EMBASE, PubMed, and two clinical trials registry databases up to 24 June 2015 were included in this review. Search terms included: low back pain, over the counter, non-steroidal anti-inflammatory (NSAID), CLBP, ibuprofen, naproxen, acetaminophen, disk herniation, lumbar spondylosis, vertebral compression fractures, spondylolisthesis, and lumbosacral muscle strain. Over-the-counter analgesics are the most frequently used first-line medication for LBP, and current guidelines indicate that over-the-counter medications should be the first prescribed treatment for non-specific LBP. Current literature suggests that NSAIDs and acetaminophen as well as antidepressants, muscle relaxants, and opioids are effective treatments for CLBP. Recent randomized controlled trials also evaluate the benefit of buprenorphine, tramadol, and strong opioids such as oxycodone. Summary This systematic review discusses current evidence pertaining to non-prescription treatment options for chronic low back pain. | A Comprehensive Review of Over the Counter Treatment for Chronic Low Back Pain | 10.1007/s40122-020-00209-w |
2021-06-01 | The prevalence of low back pain associated with disc degeneration reduced quality of life with socio-economic impact. This study is aimed at investigating the histomorphometric and antioxidant response of Brassica oleracea extract in annular puncture-induced intervertebral disc degeneration using a rabbit model. Fifteen (15) New Zealand white rabbits were used in this study and were divided into five groups ( n = 3). Group A (non-punctured) received distilled water as placebo ; group B underwent annular puncture for 4 weeks; group C underwent annular puncture for 8 weeks; group D underwent annular puncture for 2 weeks before receiving 500 mg/kg bw of Brassica oleracea extract for 2 weeks; group E underwent annular puncture for 4 weeks before receiving 500 mg/kg bw of Brassica oleracea extract for 4 weeks. The rabbits were sacrificed at 4 and 8 weeks after treatment, the discs were extracted and the histological, stereological and biochemical analysis were performed. Histological results showed lack of NP cells, disorganization in the arrangement of collagen fibres in the punctured control group (groups B and C), which was restored by Brassica oleracea extract administration after 2 and 4 weeks of treatment in the punctured-treated groups (D and E). Oxidative stress markers (CAT, SOD and GSH) levels were significantly reduced with corresponding increase in MDA among punctured-control groups but restored after 2 and 4 weeks of treatment in the punctured-treated groups. Administration of Brassica oleracea extract revealed a preventive and restorative potential in the cytoarchitecture and antioxidant level of the disc induced by annular puncture. | Histomorphometric and collagen fibers organization in annular punctured induced intervertebral disc degeneration in rabbit model: restorative and antioxidant role of Brassica oleracea | 10.1007/s13596-021-00560-z |
2021-06-01 | Background Low back pain (LBP) has been found to profoundly increase in athletes in the last decade. There are numerous treatment options available for LBP of which retrowalking seems to be a promising option for these patients; however, its potential utility in athletes is not known yet. Aim To investigate the effect of addition of retrowalking to conventional exercises on pain, range of motion, muscle fatigability, and balance in collegiate athletes with chronic mechanical LBP. Methods Subjects were screened using Oswestry Disability Index (ODI) and those having mild-to-moderate disability were included in the study. A sample of 30 athletes were randomly assigned into two groups, retrowalking + conventional exercise ( n = 15) and conventional exercise ( n = 15). Pain, flexion range of motion, balance, and muscle fatigability were examined before and after 4 weeks of the intervention. Retrowalking group performed retrowalk on a treadmill at self-paced speed for 15 min/day for 3 days per week for 4 weeks along with the conventional exercises for back pain, whereas participants in the control group performed conventional exercises alone for the same duration. Results Significant differences were observed in pain ( p = 0.003) and balance ( p = 0.003) between the groups after the intervention period, signifying greater improvement in the retrowalking group. No significant group differences were observed for flexion range of motion ( p = 0.97) and muscle fatigability ( p > 0.05). Conclusions Main findings of the present study suggest that retrowalking when added to conventional exercises may be helpful in reducing chronic mechanical LBP and improving dynamic balance. Whereas retrowalking when combined with conventional exercises has no additional effect in improving the flexion range of motion and reducing muscle fatigability. | Impact of retrowalking on pain, range of motion, muscle fatigability, and balance in collegiate athletes with chronic mechanical low back pain | 10.1007/s11332-020-00682-y |
2021-06-01 | An evident underestimation of the targeted prevention of dental diseases is strongly supported by alarming epidemiologic statistics globally. For example, epidemiologists demonstrated 100% prevalence of dental caries in the Russian population followed by clinical manifestation of periodontal diseases. Inadequately provided oral health services in populations are caused by multi-factorial deficits including but not limited to low socio-economic status of affected individuals, lack of insurance in sub-populations, insufficient density of dedicated medical units. Another important aspect is the “participatory” medicine based on the active participation of population in maintaining oral health: healthcare will remain insufficient as long as the patient is not motivated and does not feel responsible for their oral health. To this end, nearly half of chronically diseased people do not comply with adequate medical services suffering from severely progressing pathologies. Noteworthy, the prominent risk factors and comorbidities linked to the severe disease course and poor outcomes in COVID-19-infected individuals, such as elderly, diabetes mellitus, hypertension and cardiovascular disease, are frequently associated with significantly altered oral microbiome profiles, systemic inflammatory processes and poor oral health. Suggested pathomechanisms consider potential preferences in the interaction between the viral particles and the host microbiota including oral cavity, the respiratory and gastrointestinal tracts. Since an aspiration of periodontopathic bacteria induces the expression of angiotensin-converting enzyme 2, the receptor for SARS-CoV-2, and production of inflammatory cytokines in the lower respiratory tract, poor oral hygiene and periodontal disease have been proposed as leading to COVID-19 aggravation. Consequently, the issue-dedicated expert recommendations are focused on the optimal oral hygiene as being crucial for improved individual outcomes and reduced morbidity under the COVID-19 pandemic condition. Current study demonstrated that age, gender, socio-economic status, quality of environment and life-style, oral hygiene quality, regularity of dental services requested, level of motivation and responsibility for own health status and corresponding behavioural patterns are the key parameters for the patient stratification considering person-tailored approach in a complex dental care in the population. Consequently, innovative screening programmes and adapted treatment schemes are crucial for the complex person-tailored dental care to improve individual outcomes and healthcare provided to the population. | Making a complex dental care tailored to the person: population health in focus of predictive, preventive and personalised (3P) medical approach | 10.1007/s13167-021-00240-7 |
2021-06-01 | Purpose of Review The COVID-19 pandemic has posed an unprecedented challenge to healthcare, particularly in resource-constrained low and middle-income countries (LMICs). We aim to summarize the challenges faced by LMICs in providing breast cancer care during the pandemic and their response during this crisis. Recent Findings Conversion of oncology centers into COVID-19 isolation centers and lack of LMIC applicable guidelines for breast cancer treatment worsened the challenge for providers. Few LMICs changed their management framework, taking steps like triaging patients, prioritizing care, therapeutic spacing, and a shift to telehealth. Summary Modified protocols where available have served LMICs well for resource allocation; however, effectiveness of these cannot be determined due to lack of outcomes reporting. This pandemic has underscored the importance of flexibility, prompt intervention, good communication, and reassessment to address unexpected healthcare challenges and has been a learning lesson to help tailor guidelines early in the future. | The Novel Coronavirus (COVID-19) Pandemic and the Response in Low-to-Middle Income Countries | 10.1007/s12609-021-00409-z |
2021-05-29 | Low temperatures are important for the production of spring maize in northern China. While the low-temperature tolerance of maize seeds can be improved by coating them, this can result in environmental pollution, high costs, and instability. Therefore, identifying new varieties of maize is the most effective method of improving the ability of maize crops to withstand low temperatures. In this experiment, four low-temperature tolerant maize inbred lines (DNF266, Zhong 451, B73, Dan 340) and four low-temperature sensitive maize inbred lines (Luyuan 92, Ji 853, Huangzaosi, Si 144) were selected from the northern spring maize area. The griffing double-row hybridization design method was used to prepare 28 hybrid combinations. After analysing the general combining ability and the special combining ability of each combination, we found that the indoor low-temperature index and low-temperature seedings were extremely similar for all combinations. The hybridization and parental inbred lines were subjected to low-temperature treatments under both laboratory conditions and in the field. Several low-temperature indexes were assessed to identify what results could be produced from combining them. Under both treatments, the inbred line DNF266 had a higher general combining ability and the Zhong 451 × Dan 340 hybrid combination had a higher special combining ability. These results provide technical support for breeding new low-temperature varieties of maize. | Combining ability and genetic diversity under low-temperature conditions at germination stage of maize (Zea mays L.) | 10.1007/s10681-021-02865-1 |
2021-05-29 | A series of solution-processable and photosensitive polyimide (PSPI) coatings with enhanced high-temperature dimensional stability were designed, synthesized and characterized. For this purpose, the rigid-rod benzanilide (Ph − CONH − Ph) units with methyl substituents were incorporated into the molecular structures of an intrinsically auto-photosensitive PSPI system via the two-step chemical imidization copolymerization of a specially designed aromatic diamine, 2,3'-dimethyl-4,4'- diaminobenzanilide (MMDABA) and an aromatic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), together with an aromatic diamine, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane (TMMDA). The ortho -substituted methyl group in MMDABA, on one hand, was designed to guarantee the solubility of the derived PSPI resins in the organic solvents; and on the other hand, maintain the intrinsic photosensitivity of the pristine PSPI (BTDA-TMMDA, PSPI-1). Meanwhile, the rigid benzanilide unit was applied to reduce the coefficients of thermal expansions (CTE) of the derived PSPI coatings. Four PSPI copolymers with the TMMDA/MMDABA (molar ratio) of 95/5 (PSPI-2), 90/10 (PSPI-3), 85/15 (PSPI-4), and 80/20 (PSPI-5) were prepared. The derived PSPI resins were all soluble in polar aprotic solvents of N -methyl-2-pyrrolidone (NMP) and N,N -dimethylacetamide (DMAc). All the PSPI coatings maintained good photosensitivity to the ultraviolet (UV) light (UV-A, 320 ~ 460 nm) except PSPI-5, indicating the deterioration of the photosensitivity of the polymers by incorporation of MMDABA units. Incorporation of MMDABA units into the PSPI systems basically maintained the thermal stability of the polymers, while apparently increased the dimensional stability of the coatings at elevated temperatures. PSPI-5 possessed the CTE value of 42 × 10 –6 /K in the temperature range of 50 to 300 °C, which was obviously lower than that of the pristine PSPI-1 system (CTE = 56 × 10 –6 /K). | Preimidized auto-photosensitive polyimides containing methyl-substituted benzanilide units with increased high-temperature dimensional stability for advanced optical applications: preparation and properties | 10.1007/s10965-021-02591-1 |
2021-05-29 | Abstract The purpose of this study was to enhance the biosorption capacity of the aquatic biomass Callitriche obtusangula for the anionic dye Direct Red 89 in aqueous solution through chemical pretreatment. Batch experiments were carried out to determine the optimal pretreatment parameters of the biomass, such as the nature and the concentration of the activating agent and the effect of pretreatment time. The best dye removal efficiency was found to be 83%, which was obtained using the biomass treated with H 3 PO 4 , an initial dye concentration of 40 mg/L, a temperature of 20 °C, a biomass dose of 2 g/L, and a pH of 1. A number of methods of probing the structure of the biomass, including Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, specific surface area calculation, point of zero charge measurement, and the Boehm titration method, indicated that phosphoric acid acts as a dehydrating and oxidizing agent that enhances the surface area and functional groups of the biomass. Moreover, phosphoric acid promoted dye biosorption by grafting phosphate functions onto the biomass and enhancing the acid functions involved in dye fixation. Adsorption isotherm studies showed that the Freundlich model agreed well with the experimental data. In addition, the kinetics of biosorption were best described by a pseudo-second-order model. Graphic abstract | Study of the chemical pretreatment of a nonconventional low-cost biosorbent (Callitriche obtusangula) for removing an anionic dye from aqueous solution | 10.1007/s41207-021-00265-4 |
2021-05-26 | Convolution neural network is applied in image processing, and it can also carry out deep learning according to image classification. Its main advantage is that it can directly convolute the pixels related to the image, and then extract the main image features from the image. Of course, this way of processing may be closer to that of the human brain system. In this paper, the design and parameter optimization of convolution neural network are deeply studied and discussed. At the same time, the field monitoring and experimental methods are combined with historical data to further study the rainfall and runoff and sediment yield. Through the research and analysis, it is found that athletes can appropriately improve their training performance, competitive ability, and sports ability when choosing more difficult training. High-intensity training can appropriately exceed the normal psychological and bearing capacity of the human body, but if it is excessive, it will lead to physical fatigue. In the normal training process, we should consider the level of training intensity and pay attention to relaxation and recovery exercise. If we want to make the trainer recover in a short time, we should use effective means to carry out reasonable training and improve the sports ability. In the training to a certain time, the body organs may decline in function, so in the daily hard training, we should strictly grasp all aspects of scientific and comprehensive development, and coaches and athletes should timely solve the problem of recovery after sports. | RETRACTED ARTICLE:Simulation of rainfall process in mountainous regions and sports athletes’ fatigue recovery based on convolutional neural network | 10.1007/s12517-021-07364-0 |
2021-05-20 | Enzymes are the complex protein moieties, catalyze the rate of chemical reactions by transforming various substrates to specific products and play an integral part in multiple biochemical cycles. Advancement in enzyme research and its integration with industries have reformed the biotech industries. It provides a superior monetary and ecological exchange to traditional material measures in an efficient and environmentally sustainable manner. The cost-effective production of pure and highly active enzymes is still a challenge for the biocatalyst industries. The use of high purity substrates further raises the cost of a typical biocatalyst. The use of low-cost plant-based biomasses as an enticing and sustainable substrate for enzyme production is the most cost-effective approach to these problems. Given the relevance of biomass as a substrate for enzyme development, this review article focuses on the key source, composition and major enzyme generated using various biomass residues. Furthermore, the difficulties associated with the use of biomass as a substrate and technical developments in this area, are also addressed. The use of waste biomass as a substrate lowers the ultimate cost for the production of biocatalysts while simultaneously reduces the waste burden from the environment. | Cost-effective production of biocatalysts using inexpensive plant biomass: a review | 10.1007/s13205-021-02847-z |
2021-05-20 | Background Circulating tumor DNA (ctDNA) offers minimally invasive means to repeatedly interrogate tumor genomes, providing opportunities to monitor clonal dynamics induced by metastasis and therapeutic selective pressures. In metastatic cancers, ctDNA profiling allows for simultaneous analysis of both local and distant sites of recurrence. Despite the promise of ctDNA sampling, its utility in real-time genetic monitoring remains largely unexplored. Methods In this exploratory analysis, we characterize high-frequency ctDNA sample series collected over narrow time frames from seven patients with metastatic triple-negative breast cancer, each undergoing treatment with Cabozantinib, a multi-tyrosine kinase inhibitor (NCT01738438, https://clinicaltrials.gov/ct2/show/NCT01738438 ). Applying orthogonal whole exome sequencing, ultra-low pass whole genome sequencing, and 396-gene targeted panel sequencing, we analyzed 42 plasma-derived ctDNA libraries, representing 4–8 samples per patient with 6–42 days between samples. Integrating tumor fraction, copy number, and somatic variant information, we model tumor clonal dynamics, predict neoantigens, and evaluate consistency of genomic information from orthogonal assays. Results We measured considerable variation in ctDNA tumor faction in each patient, often conflicting with RECIST imaging response metrics. In orthogonal sequencing, we found high concordance between targeted panel and whole exome sequencing in both variant detection and variant allele frequency estimation (specificity = 95.5%, VAF correlation, r = 0.949), Copy number remained generally stable, despite resolution limitations posed by low tumor fraction. Through modeling, we inferred and tracked distinct clonal populations specific to each patient and built phylogenetic trees revealing alterations in hallmark breast cancer drivers, including TP53, PIK3CA, CDK4 , and PTEN . Our modeling revealed varied responses to therapy, with some individuals displaying stable clonal profiles, while others showed signs of substantial expansion or reduction in prevalence, with characteristic alterations of varied literature annotation in relation to the study drug. Finally, we predicted and tracked neoantigen-producing alterations across time, exposing translationally relevant detection patterns. Conclusions Despite technical challenges arising from low tumor content, metastatic ctDNA monitoring can aid our understanding of response and progression, while minimizing patient risk and discomfort. In this study, we demonstrate the potential for high-frequency monitoring of evolving genomic features, providing an important step toward scalable, translational genomics for clinical decision making. | Modeling clonal structure over narrow time frames via circulating tumor DNA in metastatic breast cancer | 10.1186/s13073-021-00895-x |
2021-05-17 | A new series of thermo-pH responsive polymers based on N-isopropylacrylamide and new cationic monomer has been synthesized from p -cresol in two facile steps and named by 2-((diethylamino)methyl)-4-methylphenyl acrylate), and abbreviated by (DEAMPA). It has been investigated by 1 H NMR, 13 C NMR, and FT IR. Three copolymers have been fabricated with three different molar concentrations of DEAMPA 5, 10, and 20 mol% using the free radical polymerization technique in solution. The copolymers have been chemically evaluated by 1 H NMR and FT IR as well. Moreover, the physical characterizations were also investigated; the molecular weights and dispersity by GPC, the glass transition temperature by DSC, the change in the mass by decomposition using TGA, the degree of crystallinity by X-ray diffractions, and the morphological features by SEM. The change in the lower critical solution temperature and the phase separation of polymers solutions were measured by turbidity test as the change in transmittance with temperature with concerning the change in pH and using UV–VIS spectroscopy. The new cationic thermo-pH responsive copolymer will be used in the preparation of sensors, and dual responsive hydrogel. | Poly(N-isopropylacrylamide-co-2-((diethylamino)methyl)-4-methylphenyl acrylate) thermo-ph responsive copolymer: trend in the lower critical solution temperature optimization of Poly (N-isopropyylacrylamide) | 10.1007/s10965-021-02574-2 |
2021-05-17 | Avalanche photodiodes (APDs) are well-suited for single-photon detection on quantum communication satellites as they are a mature technology with high detection efficiency without requiring cryogenic cooling. They are, however, prone to significantly increased thermal noise caused by in-orbit radiation damage. Previous work demonstrated that a one-time application of thermal annealing reduces radiation-damage-induced APD thermal noise. Here we examine the effect of cyclical proton irradiation and thermal annealing. We use an accelerated testing environment which emulates a realistic two-year operating profile of a satellite in low-Earth-orbit. We show that repeated thermal annealing is effective at maintaining thermal noise of silicon APDs within a range suitable for quantum key distribution throughout the nominal mission life, and beyond. We examine two strategies—annealing at a fixed period of time, and annealing only when the thermal noise exceeds a pre-defined limit. We find both strategies exhibit similar thermal noise at end-of-life, with a slight overall advantage to annealing conditionally. We also observe that afterpulsing probability of the detector increases with cumulative proton irradiation. This knowledge helps guide design and tasking decisions for future space-borne quantum communication applications. | Repeated radiation damage and thermal annealing of avalanche photodiodes | 10.1140/epjqt/s40507-021-00103-0 |
2021-05-17 | Background It’s necessary to analyze the related risk factors and complications of low cardiac output syndrome (LCOS) after operation in children with congenital heart disease (CHD), to elucidate the management strategy of LCOS. Methods CHD children admitted to the department of cardiology in our hospital from January 15, 2019 to October 31, 2020 were included. The personal and clinical data of CHD children with LCOS and without LCOS were collected and compared. Logistic regression analyses were conducted to identify the risk factors of postoperative LCOS. Besides, the complication and mortality of LCOS and no LCOS patients were compared. Results A total of 283 CHD patients were included, the incidence of postoperative LCOS in CHD patients was 12.37%. There were significant differences in the age, preoperative oxygen saturation, two-way ventricular shunt, duration of CPB and postoperative residual shunt between two groups (all p < 0.05). Logistic regression analyses indicated that age ≤ 4y(OR2.426, 95%CI1.044 ~ 4.149), preoperative oxygen saturation ≤ 93%(OR2.175, 95%CI1.182 ~ 5.033), two-way ventricular shunt (OR3.994, 95%CI1.247 ~ 6.797), duration of CPB ≥ 60 min(OR2.172, 95%CI1.002 ~ 4.309), postoperative residual shunt (OR1.487, 95%CI1.093 ~ 2.383) were the independent risk factors of LCOS in patients with CHD (all p < 0.05). There were significant differences in the acute liver injury, acute kidney injury, pulmonary infection, tracheotomy, duration of mechanical ventilation, length of ICU stay and mortality (all p < 0.05), no significant difference in the 24 h drainage was found( p = 0.095). Conclusion LCOS after CHD is common, more attentions should be paid to those patients with age ≤ 4y, preoperative oxygen saturation ≤ 93%, two-way ventricular shunt, duration of CPB ≥ 60 min, postoperative residual shunt to improve the prognosis of CHD patients. | Analysis of risk factors of low cardiac output syndrome after congenital heart disease operation: what can we do | 10.1186/s13019-021-01518-7 |
2021-05-13 | Metamorphic pressure–temperature conditions and sedimentary provenance were determined for the middle Permian Fanjiatun Formation in east Changchun, China, based on clay mineralogy, vitrinite reflectance and geochemical data. The pelitic rocks in the Fanjiatun Formation contain illite + kaolinite + chlorite ± mixed-layer chlorite/smectite and detrital quartz + plagioclase. Illite crystallinity in the formation varies from 0.38 to 0.49 (average = 0.44), and consists dominantly of the 2M 1 and mixed 2M 1 and 1M d polytypes. The illite b 0 dimension is 8.9860–9.0130 Å (average = 9.0010 Å), indicating the Fanjiatun Formation experienced very-low-grade metamorphism at <1.5 kbar. The metamorphic temperatures obtained based on vitrinite reflectance are 191–308 °C, indicating the formation experienced anchizone-zone facies metamorphism. Al 2 O 3 /TiO 2 ratios vary from 23.93 to 24.22 (average = 24.11), and the chemical index of alteration is 64–69 (average = 67). Rare earth element contents are high and exhibit enrichment in light rare earth elements and negative Eu anomalies. Trace element characteristics indicate that the source of the pelitic rocks was moderately weathered silicic rocks. The sediments were deposited in a reducing continental setting. | Clay mineralogy and geochemistry of pelitic rocks in the middle Permian Fanjiatun formation, East Changchun, China: implications for metamorphism and provenance | 10.1007/s12517-021-07259-0 |
2021-05-13 | Background The job one does for a living may increase ones propensity to cardiovascular diseases due to many associated risk factors. University staff may be at high risk of dyslipidaemia, a major cardiovascular disease risk factor. This study assessed prevalence of dyslipidaemia and its associated factors among the staff of University of Nigeria, Nsukka campus, Nigeria. Methods A cross-sectional survey of 386 workers selected through a 4-stage sampling technique was conducted. Data were obtained through questionnaire and lipid profile determination. Bivariate analysis using Cochran and Mantel-Haenszel test was used to determine associations between dyslipidaemia and selected variables. Odds ratios and significance at p < 0.05 were reported. Results Respondents who were 46 years and above accounted for 51.3 % while 95.3 % had tertiary education. Administrative/technical staff were 76.4 % while academic staff were only 23.6 %; 73.8 % were senior staff and 26.2 % were junior staff. More than half (60.4 %) consumed alcohol above recommendation. Lipid biomarkers of the workers were not sex dependent ( p > 0.05). Few (23.4 and 6.5 %) of the respondents had borderline high and high total cholesterol values, respectively. Whereas none (0.0 %) had low high density lipoprotein cholesterol (HDL-c), borderline low values were observed among 1.3 %. High low density lipoprotein cholesterol (LDL-c) affected 1.3 %. Triglyceride was high among 3.9 %; 20.8 % had high atherogenic index of plasma (AIP) and 2.6 % had impaired fasting blood glucose (IFBG). Dyslipidaemia had a prevalence of 54.5 % with female dominance. Hypercholesterolemia with high LDL-c was the commonest combined dyslipidaemia observed (7.8 %). Dyslipidaemia was dependent on hypercholesterolemia (OR = 0.352, 95 % C.I.=0.245–0.505), high LDL-c (OR = 0.462, 95 % C.I.=0.355-0.600) and hypertriglyceridemia (OR = 0.462, 95 % C.I.=0.355-0.600). Alcohol intake above normal was associated with almost 6 times higher risk of dyslipidaemia (OR = 5.625, 95 % C.I.=1.062–29.799). Conclusions Dyslipidaemia is a problem among the workers with hypercholesterolemia in combination with high LDL-c and hypertriglyceridemia compounding the problem. Nutrition education and physical activity are advocated to prevent cardiovascular events among the university staff. | Prevalence and associated factors of dyslipidaemia among university workers in Southeast Nigeria: a cross-sectional study | 10.1186/s13690-021-00600-9 |
2021-05-10 | Background Antimicrobial resistance (AMR) is a global public health threat and is increasingly prevalent among enteric pathogens in low- and middle-income countries (LMICs). However, the burden of multidrug-resistant organisms (MDROs) in older children, adults, and elderly patients with acute diarrhea in LMICs is poorly understood. This study’s aim was to characterize the prevalence of MDR enteric pathogens isolated from patients with acute diarrhea in Dhaka, Bangladesh, and assess a wide range of risk factors associated with MDR. Methods This study was a secondary analysis of data collected from children over 5 years, adults, and elderly patients with acute diarrhea at the International Centre for Diarrhoeal Disease Research, Bangladesh Dhaka Hospital between March 2019 and March 2020. Clinical, historical, socio-environmental information, and a stool sample for culture and antimicrobial susceptibility testing were collected from each patient. Univariate statistics and multiple logistic regression were used to assess the prevalence of MDR among enteric pathogens and the association between independent variables and presence of MRDOs among culture-positive patients. Results A total of 1198 patients had pathogens isolated by stool culture with antimicrobial susceptibility results. Among culture-positive patients, the prevalence of MDR was 54.3%. The prevalence of MDR was highest in Aeromonas spp. (81.5%), followed by Campylobacter spp. (72.1%), Vibrio cholerae (28.1%), Shigella spp. (26.2%), and Salmonella spp. (5.2%). Factors associated with having MDRO in multiple logistic regression included longer transport time to hospital (>90 min), greater stool frequency, prior antibiotic use prior to hospital presentation, and non-flush toilet use. However, pseudo-R2 was low 0.086, indicating that other unmeasured variables need to be considered to build a more robust predictive model of MDR. Conclusions MDR enteric pathogens were common in this study population with clinical, historical, and socio-environmental risk factors associated with MDROs. These findings may help guide clinical decision-making regarding antibiotic use and selection in patients at greatest risk of complications due to MDROs. Further prospective research is urgently needed to determine what additional factors place patients at greatest risk of MDRO, and the best strategies to mitigate the spread of MDR in enteric pathogens. | Multidrug-resistant enteric pathogens in older children and adults with diarrhea in Bangladesh: epidemiology and risk factors | 10.1186/s41182-021-00327-x |
2021-05-10 | Background Biopsychosocial factors above and beyond pathoanatomical changes likely contribute to the severity of chronic low back pain. A pro-nociceptive endogenous pain modulatory balance (↓inhibition and ↑facilitation) may be an important contributor to chronic low back pain severity and physical function; however, additional research is needed to address this possibility. The objective of this study was to determine whether quantitative sensory tests of endogenous pain inhibition and facilitation prospectively predict movement-evoked pain and cLBP severity self-reported on a validated questionnaire. Methods One hundred thirty-four individuals with chronic low back pain were enrolled in this two-session study. During the first study session, temporal summation of mechanical pain and conditioned pain modulation were assessed at the lumbar spine to determine endogenous pain facilitation and inhibition, respectively. One week later, participants returned for a second study session whereby they reported their pain severity and pain interference using the Brief Pain Inventory-Short Form. Movement-evoked pain and physical function capacity were assessed upon completion of the balance, walking, and transition from sit to stand tests of the Short Physical Performance Battery. Results Temporal summation of mechanical pain, but not conditioned pain modulation, significantly and prospectively predicted greater movement-evoked pain and poorer physical function on the Short Physical Performance Battery. Neither temporal summation nor conditioned pain modulation were significantly related to self-reported pain severity or pain interference on the Brief Pain Inventory-Short Form. Conclusions Findings suggest that a pro-nociceptive pain modulatory balance characterized by enhanced pain facilitation may be an important driver of movement-evoked pain severity and poor physical function in individuals with chronic low back pain. | Temporal summation of mechanical pain prospectively predicts movement-evoked pain severity in adults with chronic low back pain | 10.1186/s12891-021-04306-5 |
2021-05-10 | It will be shown analytically that the light sector of the identity block of a mixed heavy-light correlator in the large central charge limit is given by a correlation function of light operators on an effective background geometry. This geometry is generated by the presence of the heavy operators. It is shown that this background geometry is a solution to the Liouville equation of motion sourced by corresponding heavy vertex operators and subsequently that the light sector of the identity block matches the Liouville correlation function in the semi-classical limit. This method effectively captures the spirit of Einstein gravity as a theory of dynamical geometry in AdS/CFT. The reason being that Liouville theory is closely related to semi-classical asymptotically AdS 3 gravity. | The large-c Virasoro identity block is a semi-classical Liouville correlator | 10.1007/JHEP05(2021)067 |
2021-05-06 | Fracture evaluation is very important in the carbonate reservoirs, particularly fractured reservoir, due to the high impact of fractures on the reservoir permeability. Assessment of fracture parameters of reservoirs is necessary to optimize oil production. Image logs are regarded the best methods for this aim. This study aims to use electrical image logs in the Dalan and Kangan Formations reservoir in the Zagros Basin, SW Iran. This paper presents the new findings of analysis of the effective structures on reservoir quality of the Dalan and Kangan Formations in one of the Iranian gas fields by using FMI image logs. Formation micro-imager (FMI) was taken along with petrophysical logs from depth 4677–5253. FMI data were processed and evaluated. Through this assessment, different types of natural structures such as the fracture (open, close) and bedding planes were identified. The data analysis presented different fracture sets that have a different orientation to the anticline axis. All identified bed contacts were used to determine the structural dip. The general structural dip is interpreted to be 40 degrees toward N15E, with a corresponding strike of N75W-S75E. The total fractures encountered are in three categories: major-conductive, medium-conductive, and minor-conductive fractures. Fracture apertures with values more than 0.01 cm can be the highest value of fracture aperture with a value of more than 0.1 cm, which can be observed at 5013–5015 m, 5023 m, and 5065–5070 m. The range of fracture porosity from conductive fractures is computed to be 0–0.6%. Fractures with porosity range of more than 0.4% can be observed at 4953–4960 m, 4966 m, 4973–4980 m, 5020 m, 5113 m, and 5153 m (Lower Dalan). The highest fracture porosity can be observed at 4954 and 5020 m (close to 0.6%). The main productive zones appear to be 5160–5110 m, 5030–5000 m, 4980–4910 m, and 4830–4770 m. In this section of the reservoir, the high density, porosity, and aperture of the natural conductive/open fractures at certain intervals may indicate high productivity zones at these particular places. Considering the conductive/open fracture apertures, a production profile for a reservoir can be predicted from the fracture-enhanced permeability, with the assumption that the production of the reservoir is fracture-controlled. With the same assumption for the reservoirs within the 5.875-in. section of the well, a predictive production profile was constructed by integrating the fracture apertures. | Analysis of fractures in the Dalan and Kangan carbonate reservoirs using FMI logs: Sefid-Zakhur gas field in the Fars Province, Iran | 10.1007/s13146-021-00686-w |
2021-05-04 | Bituminous sub-ballast is considered as an appropriate solution for increasing the structural performance and durability of railway sub-structure. This is especially prominent due to the continuous development of trains, which are capable of circulating at ever faster speeds and transporting evermore freight. Thus, the base infrastructure for trains must also evolve both structurally and sustainably. In this sense, the use of high modulus asphalt mixtures can increase the bearing capacity of the structure, while with the addition of modified bitumen during manufacture could present a promising potential for the improvement of the structural performance and durability of the infrastructure. Therefore, this study focused on assessing the viability and potential benefits of using a high-performance asphalt mixture, manufactured with a highly rubberized low-penetration bitumen, for sub-ballast in railway tracks. To achieve this aim, the behaviour of the high-performance asphalt mixture was compared to a reference asphalt mixture, manufactured with conventional bitumen, which is typically used as bituminous sub-ballast. A series of standard laboratory tests were carried out for both mixtures, as well as two innovative tests to better assess the main failure modes expected in railway applications. In addition, a cost analysis evaluated the economic impact of the high-performance asphalt mixture in comparison with the conventional solution. Results demonstrated that the proposed mixture presented a higher bearing capacity than the conventional bituminous sub-ballast, while reducing around 50% the permanent deformations and susceptibility to cracking under similar efforts. These results indicate that the layer thickness of the modified mixture could thus be reduced by half, and still offer similar mechanical performance to the conventional mixture. In turn, this would provide a potential economic saving higher than 30%, compared to the conventional standard solution for sub-ballast. | High performance bituminous sub-ballast for improving the structural behaviour and durability of railway track substructure | 10.1617/s11527-021-01677-y |
2021-05-04 | Background Inflammatory microenvironment is significant to the differentiation and function of mesenchymal stem cells (MSCs). It evidentially influences the osteoblastogenesis of MSCs. IL-34, a newly discovered cytokine, playing a key role in metabolism. However, the research on its functional role in the osteogenesis of MSCs was rarely reported. Here, we described the regulatory effects of low-dose IL-34 on both osteoblastogenesis and osteoclastogenesis. Methods We performed the osteogenic effects of hBMSCs by exogenous and overexpressed IL-34 in vitro, so were the osteoclastogenesis effects of mBMMs by extracellular IL-34. CCK-8 was used to assess the effect of IL-34 on the viability of hBMSCs and mBMMs. ALP, ARS, and TRAP staining was used to evaluate ALP activity, mineral deposition, and osteoclastogenesis, respectively. qRT-PCR and Western blotting analysis were performed to detect the expression of target genes and proteins. ELISA was used to evaluate the concentrations of IL-34. In vivo, a rat tibial osteotomy model and an OVX model were established. Radiographic analysis and histological evaluation were performed to confirm the therapeutic effects of IL-34 in fracture healing and osteoporosis. Statistical differences were evaluated by two-tailed Student’s t test, one-way ANOVA with Bonferroni’s post hoc test, and two-way ANOVA with Bonferroni multiple comparisons post hoc test in the comparison of 2 groups, more than 2 groups, and different time points of treated groups, respectively. Results Promoted osteoblastogenesis of hBMSCs was observed after treated by exogenous or overexpressed IL-34 in vitro, confirmed by increased mineral deposits and ALP activity. Furthermore, exogenous or overexpressed IL-34 enhanced the expression of p-AKT and p-ERK. The specific AKT and ERK signaling pathway inhibitors suppressed the enhancement of osteoblastogenesis induced by IL-34. In a rat tibial osteotomy model, imaging and histological analyses testified the local injection of exogenous IL-34 improved bone healing. However, the additional IL-34 has no influence on both osteoclastogenesis of mBMMs in vitro and osteoporosis of OVX model of rat in vivo. Conclusions Collectively, our study demonstrate that low-dose IL-34 regulates osteogenesis of hBMSCs partly via the PIK/AKT and ERK signaling pathway and enhances fracture healing, with neither promoting nor preventing osteoclastogenesis in vitro and osteoporosis in vivo. | Low-dose IL-34 has no effect on osteoclastogenesis but promotes osteogenesis of hBMSCs partly via activation of the PI3K/AKT and ERK signaling pathways | 10.1186/s13287-021-02263-3 |
2021-05-02 | The dynamics of particle processes can be described by population balance equations which are governed by phenomena including growth, nucleation, breakage and aggregation. Estimating the kinetics of the aggregation phenomena from measured density data constitutes an ill-conditioned inverse problem. In this work, we focus on the aggregation problem and present an approach to estimate the aggregation kernel in discrete, low rank form from given (measured or simulated) data. The low-rank assumption for the kernel allows the application of fast techniques for the evaluation of the aggregation integral ( O ( n log n ) $\mathcal {O}(n\log n)$ instead of O ( n 2 ) $\mathcal {O}(n^{2})$ where n denotes the number of unknowns in the discretization) and reduces the dimension of the optimization problem, allowing for efficient and accurate kernel reconstructions. We provide and compare two approaches which we will illustrate in numerical tests. | Reconstruction of low-rank aggregation kernels in univariate population balance equations | 10.1007/s10444-021-09871-w |
2021-05-01 | The persistence of many micropollutants in water and wastewater is of great concern to the contemporary scientific community. Several types of advanced techniques such as heterogeneous photocatalysis are being used for the degradation of micropollutants in waters from domestic, industrial, and agricultural activities. Thus, structured photocatalytic systems are a great alternative in the development of photocatalytic reactors and continuous water treatment systems, as they present good autonomy during the treatment process. Many aspects such as type and geometry of the catalytic structure to be developed must be carefully chosen for the proper functioning of the system, as well as the best routes by which the photocatalysts will be immobilized. In this sense, this work brings the main photocatalytic coating techniques in low-cost structures for the treatment of water and wastewater contaminated with micropollutants. The methodologies and synthesis parameters that can influence the final result of the coating were highlighted, as well as the ability to reuse photocatalysts and methods for pretreating the structural surface. The dip-coating technique was the most reported among the current works due to its simplicity and, predominantly, the pretreatment techniques of the structure are still cleaning the surface with water, soap, and also some alcohols. | Structured photocatalytic systems: photocatalytic coatings on low-cost structures for treatment of water contaminated with micropollutants—a short review | 10.1007/s11356-020-10022-9 |
2021-05-01 | Abstract The stress-strain state of metal-polymeric friction pairs for vehicle brakes under low-cycle fatigue is examined from the standpoint of mesomechanics. The concepts of metal fatigue are developed in the scope of physical mesomechanics associated with studies on the damage accumulation, primarily in the field of multi-cycle fatigue. This has led to the understanding that low-cycle fatigue should correspond to a much higher level of damage accumulation in metal. A model of unsteady-state friction and fatigue modes of contacting elements is developed, wherein thermal explosions are the most characteristic features of the friction in the metal-polymeric friction pairs. It is shown that at the first stage, the internal chemical energy of the subsurface layer of the polymeric patch is converted into heat. Novel regularities concerning the onset and development of microcracks on the metal elements of friction pairs and on their operational surfaces in the presence of mechanical stress concentrators taking into account thermal stresses are established. The proposed model explains changes in the mechanism of crack propagation under the conditions of low-cycle fatigue in metal-polymeric friction pairs when air enters the crack and leads to the oxidation of fracture surfaces with the formation of a film. It is proposed that in this case the formation of surfaces with a subgrain structure occurs. The rate of the changes can be used to study the effect of cooling conditions on the kinetics of thermal processes in such friction pairs. | Mesomechanics of Metal-Polymeric Pairs in Friction Units under Low-Cycle Fatigue | 10.3103/S1068366621030053 |
2021-05-01 | In the next generation wireless communication systems operating at near terahertz frequencies, dielectric substrates with the lowest possible permittivity and loss factor are becoming essential. In this work, highly porous (98.9% ± 0.1%) and lightweight silica foams (0.025 ± 0.005 g/cm 3 ), that have extremely low relative permittivity ( ε r = 1.018 ± 0.003 at 300 GHz) and corresponding loss factor (tan δ < 3 × 10 −4 at 300 GHz) are synthetized by a template-assisted sol-gel method. After dip-coating the slabs of foams with a thin film of cellulose nanofibers, sufficiently smooth surfaces are obtained, on which it is convenient to deposit electrically conductive planar thin films of metals important for applications in electronics and telecommunication devices. Here, micropatterns of Ag thin films are sputtered on the substrates through a shadow mask to demonstrate double split-ring resonator metamaterial structures as radio frequency filters operating in the sub-THz band. | Lightweight porous silica foams with extreme-low dielectric permittivity and loss for future 6G wireless communication technologies | 10.1007/s12274-020-3201-2 |
2021-05-01 | Abstract The strength and low-temperature stability of 09Mn2Si steel are investigated. The mechanical properties of samples obtained by 3D printing (electric arc surfacing) in CNC machine tools are close to those of samples obtained from rolled sheet. In fact, the strength and yield point after 3D printing are superior. However, the low-temperature stability of 09Mn2Si steel samples obtained by electric arc surfacing is worse than for samples from rolled sheet. The results show that electric arc surfacing is promising for the 3D printing of cold-resistant materials in CNC machine tools. | Low-Temperature Stability of Manganese Steel Parts Obtained by 3D Printing from Welding Wire | 10.3103/S1068798X21050051 |
2021-05-01 | Dynamic mechanical properties of thermal aging hydroxyl-terminated polybutadiene (HTPB)-based propellant were tested using split Hopkinson pressure bar (SHPB) under low temperature (− 50 to 25 °C) and high strain rate (800–2000s −1 ). Relevant test data were obtained. Moreover, microscopic damages of thermal aging HTPB under dynamic conditions were observed through scanning electron microscopy (SEM) and micro computed tomography (CT). The test results demonstrate that the dynamic stress–strain curve of the thermal aging propellant is similar to that of non-aging propellant, and its dynamic mechanical properties show evident temperature and strain rate effects. With the increase in aging time, the dynamic compressive strength of thermal aging propellant increases continuously. Given the same aging time, the dynamic strength of the propellant is negatively related with temperature but positively correlated with strain rate. Moreover, it shows a logarithmic linear relation with strain rate. After low-temperature dynamic loading, the thermal aging propellant mainly presents damages of transgranular fractures, porosity increase, and matrix tearing. Moreover, the thermal aging propellant develops more serious impact-induced damages than the non-aging propellant. Finally, the master curve of the dynamic strength of the thermal aging propellant is obtained based on time–temperature equivalence principle. | Low-temperature dynamic mechanical properties of thermal aging of hydroxyl-terminated polybutadiene-based propellant | 10.1007/s13726-021-00902-3 |
2021-05-01 | Key message This paper demonstrates that BBX28 and BBX29 proteins in Arabidopsis promote flowering in association with the CO-FT regulatory module at low ambient temperature under LD conditions. Abstract Flowering plants integrate internal developmental signals with external environmental stimuli for precise flowering time control. The expression of BBX29 is up-regulated by low temperature treatment, but the biological function of BBX29 in low temperature response is unknown. In the current study, we examined the biological role of BBX29 and its close-related protein BBX28 in flowering time control under long-day conditions. Although neither BBX28 single mutant nor BBX29 single mutant has a flowering-associated phenotype, the bbx28 bbx29 double mutant plants have an obvious delayed flowering phenotype grown at low ambient temperature (16°C) compared to the wild-type (WT) plants. The expression of FT and TSF was lower in bbx28 bbx29 double mutant plants than in wild-type plants at 16°C. Both BBX28 and BBX29 interact with CONSTANS (CO), an important flowering integrator that directly binds to the FLOWERING LOCUS T (FT ) promoter. In the effector-reporter assays, transcriptional activation activity of CO on the FT promoter was reduced in bbx28 bbx29 double mutant plants compared to that in WT plants. Taken together, our results reveal that BBX28 and BBX29 are promoters of flowering in Arabidopsis, especially at low ambient temperature. | Two B-box domain proteins, BBX28 and BBX29, regulate flowering time at low ambient temperature in Arabidopsis | 10.1007/s11103-021-01123-1 |
2021-05-01 | Various studies and arrangements have been made in recent years to reduce the effect of refrigerants used in cooling and heating systems on climate change. Environmentally friendly refrigerants with low global warming potential are required to reduce the negative impact of air-conditioning systems on climate change. HFO and HFC/HFO refrigerant mixtures (such as R513A) are thought to replace HFC refrigerants and are also commercially produced recently. In this study, R134a, R1234yf and R513A refrigerants have been investigated theoretically and experimentally under the same operating conditions. Refrigerants were tested at the same evaporator (− 10 °C, − 5 °C and 0 °C) and condenser (35 °C) temperatures. In addition, life cycle climate performance assessment analyses of refrigerants were performed. It is found that when the evaporator temperature is − 10 °C and − 5 °C, R513A has a higher COP HP than R134a. However, R513A has a lower COP HP than R134a at 0 °C the evaporator temperature. R1234yf has a high COP HP compared to R134a at the − 10 °C evaporator temperature while it has a low COP HP at − 5 °C and 0 °C evaporator temperatures. R513A and R1234yf refrigerants have 14.45% and 17.16% less emissions than R134a, respectively. | Investigation of using R134a, R1234yf and R513A as refrigerant in a heat pump | 10.1007/s13762-020-02857-z |
2021-05-01 | The stability of betalains (Bet) encapsulated in cryogels made with a mixture of albumin (ALB) and albumin-pectin (ALB-PEC) as wall materials were evaluated during storage at 32% and 83% relative humidity (RH) at several different temperature conditions (4 °C, 30 °C and 40 °C). The retention of betalains (betanin + isobetanin) and phenolic compounds and the antioxidant activity were determined by high-performance liquid chromatography, the Folin–Ciocalteu method and radical ABTS *+ capture methodology. The color parameters and images of the encapsulated betalains were obtained. Cryogels prepared with ALB at 32% RH and at 4 °C provided betanin and isobetanin retention of 72% and 82%, with half-life times of 108 and 165 days, respectively. The antioxidant activity and phenolic compounds showed retention greater than 70% during storage at 32% RH at all temperatures. Cryogels prepared with ALB-PEC also conferred high retention percentages of phenolic compounds at 83% RH, but this high RH caused a significant decrease in the retention of betalains. Both ALB and ALB-PEC improved betalain stability during storage compared with the extracts without encapsulating. Therefore, cryogels could be used as protection matrices for betalains. | Effect of temperature and relative humidity on the stability of betalains encapsulated in cryogels from protein and polysaccharide | 10.1007/s13197-020-04713-x |
2021-05-01 | Abstract The effects of the low-temperature plasma exposure, gg irradiation, and combined γ irradiation and plasma exposure on the structure and surface properties of thin films based on polylactic acid (PLA) are studied. Films are prepared by the solvent casting method. It is shown that films based on polylactic acid have topographically different sides: a smoother inner side and an embossed outer one. PLA films have properties close to hydrophobic ones, with a contact angle in the range of 70°–73° regardless of the surface side. They belong to weakly polar materials. The combined effect of plasma and gg irradiation slightly changes the surface topography. The effect of low-temperature plasma on the surface of the films leads to a decrease in the contact angle by 13°–55° (9–11%) and an increase in the surface energy due to the polar component. The results of in vivo experiments on rabbits are presented. Biomicroscopy, optical coherence tomography, and morphological and electron microscopic examination of the cornea after implantation of the initial and radiation- and plasma-treated films show that implantation of the films in the anterior chamber is not accompanied by a pronounced inflammatory reaction and increased intraocular pressure, while maintaining the morphological structure of the cornea almost unchanged. | Effect of Low-Temperature Plasma Treatment and γ Irradiation on the Surface Properties of Thin Films Based on Polylactic Acid | 10.1134/S207511332103014X |
2021-05-01 | Here we present a novel approach of intercritical heat treatment for microstructure tailoring, in which intercritical annealing is introduced between conventional quenching and tempering. This induced a heterogeneous microstructure consisting of soft intercritical ferrite and hard tempered martensite, resulting in a low yield ratio (YR) and high impact toughness in a high-strength low-alloy steel. The initial yielding and subsequent work hardening behavior of the steel during tensile deformation were modified by the presence of soft intercritical ferrite after intercritical annealing, in comparison to the steel with full martensitic microstructure. The increase in YR was related to the reduction in hardness difference between the soft and hard phases due to the precipitation of nano-carbides and the recovery of dislocations during tempering. The excellent low-temperature toughness was ascribed not only to the decrease in probability of microcrack initiation for the reduction of hardness difference between two phases, but also to the increase in resistance of microcrack propagation caused by the high density of high angle grain boundaries. | Determining role of heterogeneous microstructure in lowering yield ratio and enhancing impact toughness in high-strength low-alloy steel | 10.1007/s12613-020-2235-5 |
2021-05-01 | Abstract The channel pipes of the control and safety systems of RBMK-1000 reactors are made of a Zr–2.5% Nb (E125) alloy and must operate for 45 years. The evolution of the alloy structure under the action of long-term low-temperature neutron irradiation is studied. The grain structure of the alloy is shown to be stable; annealing of initial dislocations and the formation of radiation-induced defect take place. Radiation-induced diffusion processes, which lead to a decrease in the niobium content in β-Nd precipitates and the appearance of new fine-grained precipitates in the alloy matrix, are revealed. | Structural Evolution of a Zr–2.5% Nb Alloy during Long-Term Low-Temperature Neutron Irradiation | 10.1134/S0036029521050025 |
2021-05-01 | Abstract— A mechanism is suggested to explain the transport of sulfide material by means of its dissolution and subsequent redeposition under the effect of an ascending infiltrating flow of intercumulus melt during the compaction of cumulates in layered plutons. Evidences of this process are observable in the Burakovo–Aganozero intrusion. Analysis of data on Cu concentrations in rocks of the pluton (more than 10 000 samples of core material from 160 boreholes) reveals two distribution types of the low-sulfide mineralization. The vertical sections of the first type are characterized by mineralization distributed throughout the whole thickness of the lower unit of clinopyroxene–orthopyroxene ( Cpx – Opx ) cumulates and the almost absolute absence of sulfides in all overlying rocks. In the second type, Cu mineralization is constrained to the top part of this unit of clinopyroxene–orthopyroxene ( Cpx – Opx ) cumulates, and the overlying rock sequence of the zone of clinopyroxene–orthopyroxene–plagioclase ( Cpx – Opx – Pl ) cumulates includes intensely mineralized rocks. Physicochemical analysis within the scope of D.S. Korzhinskii’s theory of acid–basic interaction and numerical simulations of the effects of major components of the melt on the solubility of the sulfide phase indicate that Ca and Mg play an important role in the liquid immiscibility/dissolution of the sulfides. A model is proposed for the origin of the low-sulfide mineralization of this pluton: clinopyroxene emergence on the liquidus resulted in the onset of liquid immiscibility of sulfide and produced Cu distribution of the first type. The infiltration of the intercumulus melt during the compaction of the cumulus material led to the dissolution and upward transport of the sulfide material for hundreds of meters and thus produced Cu distribution of the second type. | Infiltration of Intercumulus Liquid as a Process for the Sulfide Relocation—An Example from Low-Sulfide Mineralization of the Burakovo–Aganozero Intrusion | 10.1134/S0016702921050050 |
2021-05-01 | In order to explore the effect of a small amount of rare earth addition in ultra-cleaned pipeline steel and the influence of the cooling process on the tensile and impact properties, three API X80 pipeline steels were fabricated by varying RE addition and the cooling process at the same time. Three microstructures with different features for a low C high Nb microalloyed high-strength pipeline steel and the corresponding mechanical properties were investigated. The results showed that even in the ultra-cleaned steel with O and S contents less than 10 ppm, the addition of RE would still cause an increase in the volume fraction of inclusions consisting of complicated RE oxysulfide and RE sulfide. More inclusions formed in the 112 ppm RE steel were harmful to the low temperature toughness, while few inclusions formed in the 47 ppm RE steel had almost no influence on the low temperature toughness. The two RE additions had no effect on strength of the steels. As the finishing cooling temperature was increased and the cooling rate was decreased within a certain range, the volume fractions of polygonal ferrite and quasi-polygonal ferrite as well as the number density and size of martensite–austenite islands were increased. Under such combined effect, the strength of the steels had almost no change. As the finishing cooling temperature was increased from 481 to 584 °C and the cooling rate was reduced from 20 to 13 °C/s, for the steel with 112 ppm addition of RE, there was an obvious decrease in the low temperature toughness. The reduced value (about 33 J) of the USE of steel consisted of two parts including the influence (about 18 J) of more inclusions formed due to 112 ppm addition of RE and the effect (about 15 J) of the lower high-angle grain boundaries. | Effect of Rare Earth and Cooling Process on Microstructure and Mechanical Properties of an Ultra-Cleaned X80 Pipeline Steel | 10.1007/s40195-020-01151-8 |
2021-05-01 | Abstract Mixtures of low-density polyethylene ( T m = 108°C, enthalpy of melting 80 J g –1 ) with 90 wt % indigo, lophine, bromcresol purple, spiropyran, phenol red, rhodamine, phenolphthalein, and fluorescein were subjected to plastic deformation under a pressure of 1 GPa on an anvils-type high-pressure apparatus. The study of deformed mixtures was carried out by the DSC method. The thermograms of heating the mixtures showed peaks of polymer melting with enthalpies, which varied from 25 to 170 J g –1 . The thermograms below the polymer temperature showed either endotherm peaks of melting of fine crystallites with maxima at 44–57°С, the enthalpies of which varied within 20–120 J g –1 , or exotherm peaks of crystallization of fine crystallites with maxima at 58–67°С and enthalpies from 20 up to 45 J g –1 . In the range of 81–86°С, in some mixtures, the exotherm process of cold polymer crystallization took place, the enthalpy of which varied from 75 to 290 J g –1 . At temperatures above the polymer T m in the range 115–132°С, the heating thermograms showed exotherm peaks with enthalpies from 115 to 420 J g –1 , while, in the range 137–164°С, they showed endotherm peaks with enthalpies of 520–540 J g –1 . Crystallization of most mixtures from the melt was described by two peaks, one of which was always at 87°С, while the other could be at 48 or 112°С. The total enthalpies of crystallization varied from 40 to 82 J g –1 . | Exothermic Effects in Mixtures of Low-Density Polyethylene with 90 wt % of Low-Molecular-Weight Organic Compounds after Plastic Deformation under High Pressure | 10.1134/S2070205121030266 |
2021-05-01 | The current stage of development of promising gas and gas-condensate fields on the territory of Russia is realized at the extracting plants whose products contain carbon dioxide (CO 2 ). The presence of carbon dioxide, in combination with moisture and other factors, stimulates the intense development of corrosion processes and requires careful and well-justified analysis of the corrosion activity of working media with subsequent choice of the engineering solutions ensuring the reliable safe operation of hydrocarbon-extracting plants. We analyze the accumulated experience of testing of carbon steels and corrosion-resistant alloys in the presence of aggressive CO 2 , which leads to the development of dangerous local corrosion defects. These defects are developed especially rapidly under the conditions of condensation of moisture, which is most intensely accumulated in the process of the gas extraction in the first sections of the pipeline for the highest temperature drops. The tests carried out at the Gazprom VNIIGAZ, LLC demonstrated that local defects may develop on carbon and low-alloy steels (such as 09G2S steel) under the operating conditions of extracting plants in the presence of CO 2 and moisture condensation. Especially high corrosion resistance was exhibited only by the alloy whose chromium content is ≥ 13%. | Corrosion Activity of Operating Conditions for the Steel Equipment and Pipelines in the Plants Extracting CO2-Containing Gases | 10.1007/s11015-021-01132-x |
2021-05-01 | This study combines the thermodynamic analysis of a polygeneration system along with the numerical modelling of the thermal behavior of geothermal reservoirs in Mexico to exploit their energy. Each reservoir was modeled as a porous medium assuming a five-spot well configuration and local thermal equilibrium. The heat conduction-convection along with the Laplace equations were solved to compute temperature distributions, the useful life and the optimum distance between injection-extraction wells. The predicted temperature and pressure of the geothermal fluid at the outlet of the reservoir were exploited in the polygeneration system consisting of: (1) a Rankine cycle, (2) an absorption refrigeration cycle, and (3) a heat exchanger. The developed approach allows calculating both the optimal distance between injection-extraction wells and the global (utilization) efficiency of six arrangements (each composed by a reservoir connected to a polygeneration system) by assuming that reservoirs have a lifespan of 30 years. Results also show that: (a) due to the low efficiency of the Rankine cycle, very little thermal energy is converted into electrical one; (b) not only the temperature and the size are important when evaluating the power production performance of reservoirs, but also the permeability plays a fundamental role; (c) the first law efficiency of the polygeneration system ranges from 41.9% to 43.7%; (d) the utilization efficiency of the six arrangements lies in the range between 25.8% and 31%. | Polygeneration Study of Low-to-Medium Enthalpy Geothermal Reservoirs in Mexico | 10.1007/s11630-020-1271-9 |
2021-05-01 | Abstract The effect of salicylic acid (SA) on the reaction of cucumber plants ( Cucumis sativus L.) on the effect of low positive temperatures has been studied. It was found that treatment with SA promotes a decrease in the release of electrolytes from the tissues of cotyledonous leaves of seedlings exposed to subdamaging (12°C) and damaging (4°C) temperatures. In the leaves of seedlings treated with SA and exposed to cold, a higher activity of superoxide dismutase, catalase, and guaiacol-specific peroxidase was recorded as well as an increase in the accumulation of transcripts of the genes encoding them ( CuZnSOD and CAT ) compared to the control variant (without SA treatment). Under the action of low temperatures (12 and 4°C) on seedlings, SA also reduced the formation of one of the end products of lipid peroxidation, malondialdehyde, in seedling leaves. It was concluded that SA has a protective effect on cucumber seedlings when exposed to low positive temperatures, which is expressed in the activation of antioxidant enzymes and a decrease in the level of oxidative stress. | Effect of Salicylic Acid on Antioxidant Enzymes and Cold Tolerance of Cucumber Plants | 10.1134/S1021443721020059 |
2021-05-01 | The hydrogen effect on strength, ductility, low-cycle life, and cyclic crack resistance parameters of steels of different structural classes and a heat-resistant nickel alloy is studied in the range of load rates of 0.01–100 mm/min, amplitudes and frequencies of low-cycle bending of 0.8–1.6% and 8.3·10 –3 – 8.3·10 –1 , respectively, and fatigue loading of beam specimens at frequencies of 0.5–50 Hz. A maximum hydrogen effect on the ductility of 38KhN3MFA (35NiCrMoV15-5) and 13Kh11N2V2MF (1.5Ni0.5Mo2W) steels and a KhN56MBYuD (56Ni6Mo4Nb) alloy was revealed in the range of load rates of 0.01–1 mm/min and for 05Kh11N23T3MR (23Ni1.5Mo3Ti) steel, it is at rates ≤ 0.1 mm/min. The hydrogen embrittlement of all materials in low-cycle bending and cyclic crack resistance tests was established to significantly weaken with the load frequency. With the strain amplitude, the hydrogen sensitivity of 38KhN3MFA steel (residual austenite and highly dispersed sorbite) decreases and that of 13Kh11N2V2MF steel increases, while the hydrogen embrittlement degree of austenitic materials is almost independent of the amplitude. A decrease in the load frequency from 50 to 5 Hz leads to a decrease in the cyclic crack resistance threshold and contributes to a significant crack acceleration in the presence of hydrogen in the middle section of the kinetic fatigue fracture diagrams. | Load Rate-Related Mechanical Properties of Steels and Alloys under Static and Cyclic Loading in Gaseous Hydrogen | 10.1007/s11223-021-00303-0 |
2021-05-01 | Basalt fibre-reinforced plastic sheet (BFRP) enhancement is one of the strengthening methods suitable for concrete structures due to the low price and high tensile strength of BFRPs. It is of great importance to study the mechanical performance of BFRP-reinforced low-strength concrete structures in freeze–thaw environments. Therefore, 15 concrete beam specimens were designed, and a fast freeze–thaw experiment was conducted in this research to consider different parameters, such as the number of freeze–thaw cycles, sequence of freezing–thawing and BFRP pasting and other factors. The mechanical performance of low-strength concrete beams reinforced with BFRPs under freeze–thaw cycles was investigated. The failure mode and load–deflection curves of specimens were also analysed. The test results revealed that the ultimate strength of concrete beams reinforced with BFRPs was greatly improved, with a maximum increase of 32.7%. With increasing number of freeze–thaw cycles, the ultimate strength of beams gradually decreased over the bearing capacity of non-frozen-thawed concrete beams reinforced with BFRPs (F0b), and the bearing capacity of low-strength concrete beams reinforced with BFRPs decreased 17.1% after 50 continuous freeze–thaw cycles, while the beam failure mode changed from bending failure to shear failure accompanied by de-bonding failure. A mechanical model of BFRP-reinforced low-strength concrete beams was constructed under the de-bonding failure mode, and a calculation equation to determine the magnitude of de-bonding failure was proposed. Finally, finite element analysis of specimens was performed with cohesive elements to simulate the nonlinear softening mechanical behaviour of the BFRP–concrete interface. | Experimental and Theoretical Research on Low-Strength Concrete Beams Reinforced with Basalt Fibre-Reinforced Plastic Sheets in a Freeze–Thaw Environment | 10.1007/s13369-020-05249-0 |
2021-05-01 | Abstract Mixtures of low-density polyethylene ( T m = 108°C; enthalpy of melting, 80 J g −1 ) with various low-molecular-weight organic components have been subjected to plastic deformation under a pressure of 1 GPa on an anvil-type high-pressure device. Melamine, cyanuric acid, adamantane, tetracene, fumaric acid, succinic acid, aspartic acid, indigo, anthracene, methyl orange, congo red, and safranin have been used as a low-molecular-weight component. The deformed mixtures have been studied using the DSC method. The thermograms of the mixtures at temperatures below the polymer T m exhibited both endothermic and exothermic peaks. The endotherms and exotherms have been associated with the melting of small polymer crystallites and the crystallization or recrystallization processes in the polymer phase, respectively. In some mixtures, thermal effects were detected at temperatures above the polymer T m , 117–161°C. These effects have been attributed to electrostatic interaction at the polymer/low-molecular-weight component interfaces. | Influence of Low-Molecular-Weight Organic Compounds on Thermal Effects in Their Mixtures with Low-Density Polyethylene after High-Pressure Plastic Deformation | 10.1134/S0018143921020120 |
2021-05-01 | A concept is developed for assessing the stability of untransformed austenite entering the martensite-austenite component of a bainitic structure, which is determined by the action of hydrostatic stresses caused by difference in the specific volumes of the austenite and ferrite phases. Relations describing the thermal stability of austenite in the M/A phase are derived. The former is affected by the volume fraction of the phase, the fineness, the size distribution, and the difference in the coefficients of thermal expansion of the austenite and of the ferrite component of the bainite. | Stability of Untransformed Austenite in M/A Phase of Bainitic Structure of Low-Carbon Steel | 10.1007/s11041-021-00648-y |
2021-05-01 | Abstract This paper describes the preparation, broad characterization and study of activity in hydrogenation and hydroformylation reactions of an easily produced 0.18% Rh/Al 2 O 3 . Analytical studies on fresh and recycled samples shed light on the smart properties of such catalyst. Results showed high activity as well as fine/excellent chemoselectivity or regioselectivity, characteristics that may suggest a wide range of applicability. Graphic Abstract The low metal content catalyst 0.18% Rh/Al 2 O 3 was very active in both hydrogenation and hydroformylation reactions so providing intermediates for valuable APIs, as Nabumetone and Eletriptan, and a fragrance with a fresh, green-floral smell, that recalls scent of lily of the valley. | A Low Rhodium Content Smart Catalyst for Hydrogenation and Hydroformylation Reactions | 10.1007/s10562-020-03407-5 |
2021-05-01 | Physical modeling of microalloyed low-carbon steel cooling in a dilatometer under intense cooling conditions is studied. A comparative study of the potential of intense cooling during which the metal cooling rate achieved exceeds by several factors the potential of standard laminar units is provided. Potential versions of section location for intense cooling are determined on the example of mill 1950. The effect of early intense cooling strategies on the change in hardness and strength is demonstrated. The effect of later cooling parameters on the final microstructure, including the M/A component, is also demonstrated. | Effect of Hot-Rolled Strip Intense Post-Deformation Cooling Parameters on Structure Formation Processes in Low-Carbon Steels | 10.1007/s11015-021-01130-z |
2021-05-01 | In this article, the influence of simulated thermal cycles for the heat-affected zone (HAZ) on the microstructural evolution and mechanical properties in a low-carbon high-strength Cu-bearing steel was investigated by microstructural characterization and mechanical tests. The results showed that the microstructure of the coarse-grained heat-affected zone (CGHAZ) and the fine-grained heat-affected zone (FGHAZ) was mainly comprised of lath martensite, and a mixed microstructure consisting of intercritical ferrite, tempered martensite and retained austenite occurred in the intercritically heat-affected zone (ICHAZ) and the subcritically heat-affected zone (SCHAZ). Also, 8–11% retained austenite and more or less Cu precipitates were observed in the simulated HAZs except for CGHAZ. Charpy impact test indicated that the optimum toughness was obtained in FGHAZ, which was not only associated with grain refinement, but also correlated with deformation-induced transformation of the retained austenite, variant configuration as interleaved type and a relatively weak variant selection. The toughness of ICHAZ and SCHAZ exhibited a slight downtrend due to the presence of Cu precipitates. The CGHAZ has the lowest toughness in the simulated HAZs, which was attributed to grain coarsening and heavy variant selection. In addition, the contribution of Cu precipitates to yield strength in simulated HAZs was estimated based on Russell–Brown model. It demonstrated an inverse variation trend to toughness. | On the Microstructural Strengthening and Toughening of Heat-Affected Zone in a Low-Carbon High-Strength Cu-Bearing Steel | 10.1007/s40195-020-01159-0 |
2021-05-01 | An attempt was made to increase the solubility of High Level liquid Waste (HLW), mainly Cr and Mo, by addition of P 2 O 5 to sodium borosilicate glass. A total of seven different phosphorus containing alkali borosilicate glass samples were in-house fabricated. As a part of chemical quality control, concentrations of four low Z elements namely Si, Na, B and P were determined by in situ current normalized external (in air) Particle Induced Gamma-ray Emission (PIGE) method using low energy proton beam from Folded Tandem Ion Accelerator (FOTIA), BARC. PIGE method was validated by analyzing synthetic elemental standards and suitable certified reference materials. Phosphorus has shown thermal losses during fabrication. | Simultaneous quantification of low Z elements in phosphorus containing alkali borosilicate glass samples by in situ Current normalized external (in air) PIGE method utilizing proton beam from FOTIA | 10.1007/s10967-021-07679-y |
2021-05-01 | Potassium-ion batteries (KIBs) are promising candidates for large-scale energy storage due to the abundance of potassium and its chemical similarity to lithium. Nevertheless, the performances of KIBs are still unsatisfactory for practical applications, mainly hindered by the lack of suitable cathode materials. Herein, combining the strong inductive effect of sulphate and the feasible preparation of Fe 2+ -containing compounds in oxalate system, a compound with novel architecture, K 4 Fe 3 (C 2 O 4 ) 3 (SO 4 ) 2 , has been identified as a low-cost and environmentally friendly cathode for stable potassium-ion storage. Its unique crystal structure possesses an unprecedented two-dimensional framework of triple layers, with 3.379 Å interlayer distance and large intralayer rings in the size of 4.576×6.846 Å. According to first-principles simulations, such a configuration is favorable for reversible K-ion migration with a very low volume change of 6.4%. Synchrotron X-ray absorption spectra and X-ray diffraction characterizations at different charging/discharging states and electrochemical performances based on its half and full cells further verify its excellent reversibility and structural stability. Although its performance needs to be improved via further composition tuning with multi-valent transition metals, doping, structural optimization, etc., this study clearly presents a stable structural model for K-ion cathodes with merits of low cost and environmental friendliness. 得益于钾的地壳丰度及其与锂的化学相似性, 钾离子电池有 望应用于大规模储能领域. 目前, 钾离子电池的性能尚不能满足实 用需求, 主要原因在于缺乏合适的正极材料. 基于硫酸根的强诱导 效应和草酸体系制备亚铁化合物的优势, 本文制备了一种新型廉 价、环境友好且稳定的储钾正极材料K 4 Fe 3 (C 2 O 4 ) 3 (SO 4 ) 2 . 其独特 的二维层状晶体结构具有3.379 Å的层间距, 且层内具有4.576 × 6.846 Å的大环. 根据第一性原理计算, 该结构有利于钾离子的可逆 迁移, 且体积变化仅为6.4%. 不同充放电态样品的同步辐射X射线 吸收光谱和XRD、半电池以及全电池的电化学表征证实了其优异 的电化学可逆性和结构稳定性. 通过成分调控、掺杂、结构优化 等策略, K 4 Fe 3 (C 2 O 4 ) 3 (SO 4 ) 2 正极材料的电化学性能有望进一步提 升. 因此, 本工作为廉价、环保的储钾正极材料提供了一种新的稳 定晶体模型. | A novel low-cost and environment-friendly cathode with large channels and high structure stability for potassium-ion storage | 10.1007/s40843-020-1512-0 |
2021-05-01 | Abstract n- Propyl bromide has substantial industrial importance, mainly in the field of agrochemicals and pharmaceuticals. The present work provides an improved, efficient, cost effective and industrially scalable preparation of n- propyl bromide starting from n- propanol, liquid bromine and sulfur with yields up to 95%. The levels of unwanted products like water content, n- propanol and isopropyl bromide are below 0.1, 0.05 and 0.04% respectively. | An Improved Process for Industrial Production of n-Propyl Bromide | 10.1134/S1070427221050189 |
2021-05-01 | Bacteria growth depends crucially on protein synthesis, which is limited by ribosome synthesis. Ribosomal RNA (rRNA) transcription is the rate-limiting step of ribosome synthesis. It is generally proposed that the transcriptional initiation rate of rRNA operon is the primary factor that controls the rRNA synthesis. In this study, we established a convenient GFP-based reporter approach for measuring the bacterial rRNA chain elongation rate. We showed that the rRNA chain elongation rate of Escherichia coli remains constant under nutrient limitation and chloramphenicol inhibition. In contrast, rRNA chain elongation rate decreases dramatically under low temperatures. Strikingly, we found that Vibrio natriegens , the fastest growing bacteria known, has a 50% higher rRNA chain elongation rate than E. coli , which contributes to its rapid ribosome synthesis. Our study demonstrates that rRNA chain elongation rate is another important factor that affects the bacterial ribosome synthesis capacity. | Control of ribosome synthesis in bacteria: the important role of rRNA chain elongation rate | 10.1007/s11427-020-1742-4 |
2021-05-01 | A fundamental difference between the grain size composition of cement-free refractory concretes (CFRC) from low- and ultra-low-cement concretes is presence within their composition of up to 2 – 3 % nanoparticles (<0.1 μm) that determine increased reactivity. During selection of the optimum CFRC grain size composition in order to achieve the densest particle packing there is often use of “ideal curves” in accordance with Andreasen and Furnas equations. The specific nature of the use of porous fillers in the production of CFRC is considered. The strength of ceramic concrete with porous aggregates significantly exceeds the strength of the aggregates themselves. | Cement-Free Refractory Concretes. Part 7. Concrete Mix Properties and their Grain Size Distribution | 10.1007/s11148-021-00556-x |
2021-05-01 | Abstract Loy Yang lignite was pyrolyzed under nitrogen atmosphere in a tube furnace. The changes in physicochemical properties during low-temperature pyrolysis process and their effects on water re-adsorption capacity were investigated. All the samples were characterized by X-ray photoelectron spectroscopy, zeta potential, N 2 adsorption–desorption analyzer, and scanning electron microscopy. Moreover, equilibrium water contents (EWCs) across a range of relative humidities (RHs) were measured. The results showed that oxygen-containing functional groups continuously decreased in the temperature range of 180–300°C; in contrast, pore volume increased mainly due to the release of volatiles. Note that the pore volume of the sample treated at 300°C increased substantially relative to those of the other samples. Furthermore, the EWCs of the treated samples decreased compared with that of raw lignite. For the microscopic description of the process, at low RHs the decrease in oxygen-containing functional groups corresponds to the decrease in EWC. At high RHs the competitive effects of the decrease in oxygen-containing functional groups and increase in pore volume account for the changes in EWC. | Effects of Low-Temperature Pyrolysis in a Tube Furnace on Water Re-adsorption of Loy Yang Lignite and Microscopic Description of the Process | 10.3103/S0361521921030125 |
2021-05-01 | To investigate low air pressure effect on the flame radiative feedback to the fuel surface, pool fires with stable liquid surface were performed by employing three round burners with diameters of 0.15 m, 0.25 m and 0.35 m in both Lhasa (3650 m/64 kPa) and Hefei (24 m/100.8 kPa). Incident heat flux at fuel surface, flame shape and axial temperature distribution were compared at two sites. The flame envelope for 0.15 m appears to be cylinder, while that for 0.35 m tends to be cone, and the mean flame height is larger in reduced pressure for the same pool dimension. The averaged flame temperature is relatively higher in Lhasa due to reduction in air entrainment and thermal radiation loss, and the axial temperature rises could be scaled in the form of $$z\left( {{P \mathord{\left/ {\vphantom {P Q}} \right. \kern-0pt} Q}} \right)^{2/5}$$ z P / Q 2 / 5 . Experimental findings also reveal that low pressure reduces the radiation feedback evidently for different scale pool fires and the averaged value could be correlated against $$T_{\text{f}}^{5} P^{2} L_{\text{m}}$$ T f 5 P 2 L m . The radiation feedback fraction $$X_{\text{a}}$$ X a is around 0.30 for 0.15 m pool fires, while it is 0.55 in Lhasa for 0.35 m pool fire, lower than 0.76 in Hefei. | Experimental study of reduced pressure effect on radiation feedback to the fuel surface of pool fires | 10.1007/s10973-020-09545-7 |
2021-05-01 | The natural science in GEO-6 makes clear that a range and variety of unwelcome outcomes for humanity, with potentially very significant impacts for human health, become increasingly likely if societies maintain their current development paths. This paper assesses what is known about the likely economic implications of either current trends or the transformation to a low-carbon and resource-efficient economy in the years to 2050 for which GEO-6 calls. A key conclusion is that no conventional cost–benefit analysis for either scenario is possible. This is because the final cost of meeting various decarbonisation and resource-management pathways depends on decisions made today in changing behaviour and generating innovation. The inadequacies of conventional modelling approaches generally lead to understating the risks from unmitigated climate change and overstating the costs of a low-carbon transition, by missing out the cumulative gains from path-dependent innovation. This leads to a flawed conclusion as to how to respond to the climate emergency, namely that significant reductions in emissions are prohibitively expensive and, therefore, to be avoided until new, cost-effective technologies are developed. We argue that this is inconsistent with the evidence and counterproductive in serving to delay decarbonisation efforts, thereby increasing its costs. Understanding the processes which drive innovation, change social norms and avoid locking in to carbon- and resource-intensive technologies, infrastructure and behaviours, will help decision makers as they ponder how to respond to the increasingly stark warnings of natural scientists about the deteriorating condition of the natural environment. | The costs and benefits of environmental sustainability | 10.1007/s11625-021-00910-5 |
2021-05-01 | Cobaltites with the general formula ACoO 3 exhibit a wide variety of physical properties. Cobaltite Pr 0.5 Ca 0.5 CoO 3 exhibits a metal–insulator transition accompanied by a structural shift with a delocalized intermediate spin state ( $$t_{2g}^{5} e_{g}^{1}$$ t 2 g 5 e g 1 ) or $$S^{*}$$ S ∗ at high temperature. In this work, Pr 0.5− x Sm x Ca 0.5 CoO 3− δ ( x = 0.02, 0.04, 0.06, and 0.08) perovskites were synthesized by the standard solid-state method. Rietveld analysis for experimental X-ray diffraction (XRD) patterns showed that the samples crystallize in an orthorhombic structure with space group Pnma (62). Zero field cooling-field cooling (ZFC–FC) magnetization curves, at a temperature range from 50 to 300 K, show paramagnetic behaviors in each of the Sm doped samples. The analysis of magnetization curves suggests that the samples exhibit a short-range ferromagnetic phase at 50 K and a Co low spin (LS) state in the paramagnetic regime. | Possible Co3+ Low Spin State in Pr0.5−xSmxCa0.5CoO3−δ Induced by Sm Doping | 10.1007/s10909-021-02587-7 |
2021-05-01 | In this paper; we propose DMDG-GDOV TFET device structure for low leakage current. Considering the potential benefits of DMDG-TFET, emphasize with Gate Drain Overlap (GDOV) has been simulated with high-k (HfO 2 ) and low-k (SiO 2 ) which results in elevated ON current (I ON ) as well as less leakage current. The gate region and drain region overlap shows low leakage current as compared to non-overlap gate terminal on drain side in DMDG-TFET. This gate-region on drain-region overlap reduces the electric field in the ambipolar condition and exhausts the carrier in the drain terminal side away from the junction. However, gate electrode overlapped on drain side inevitably enhances the gate-to drain capacitance (C GD ) i.e. Miller Capacitance due to increase in overlap capacitance (C OV ) and inversion capacitance (C inv ). Hence by using high-k dielectric and low-k dielectric deposition over channel region and source-drain region respectively with dual-metal gate technique, the C GD capacitances has been reduced. This C GD further reduces the intrinsic delay by adjusting the gate metal work function of dual metal where Ф Tgate is (4.3 eV) greater than Ф Sgate (4.1 eV). | Dual-Material Gate-Drain Overlapped DG-TFET Device for Low Leakage Current Design | 10.1007/s12633-020-00547-6 |
2021-05-01 | Anthocyanin accumulation is a characteristic response to phosphate (Pi) deficiency in plants. In the present study, we investigated the role of maize anthocyanins (MA) in alleviating low Pi (LP) stress in maize ( Zea mays L). To this end, maize plants were exposed to LP conditions and treated with or without (control) MA. Interestingly, MA-treated maize plants showed relieved growth inhibition, reproductive development retardation, and yield loss compared to control plants under LP stress. Moreover, the level of oxidative destruction was significantly alleviated in MA-treated plants compared to the untreated control under conditions of LP stress. Acid phosphatase (APase) activity was significantly higher in MA-treated plants than in control plants, resulting in enhanced Pi mobilization and recycling. The results of the transcriptome analysis suggested that genes involved in photosynthesis, photosystem light harvesting, Pi transport, and recycling were differentially expressed between MA-treated plants and control plants. Moreover, metabolome analysis indicated higher sugar and organic acid levels and lower phosphorylated metabolite contents in MA-treated plants than in control plants, which was consistent with the results of the comparative transcriptome analysis. Taken together, our findings indicate that MA plays critical roles in alleviating LP stress in maize plants, probably by improving photosynthetic performance and increasing Pi mobilization and recycling. | Transcriptomic and metabolomic profiling reveals the protective role of anthocyanins in alleviating low phosphate stress in maize | 10.1007/s12298-021-00981-9 |
2021-05-01 | Abstract It is proposed to use transistor-transistor logic (TTL) for future fast, low-power digital electronic circuits. A relaxation quantum transistor can be the basic element of these circuits. This approach allows us to circumvent the difficulties of using field effect transistors based on nanowires. | Digital Circuits Based on Quantum Transistors | 10.1134/S1063739721030033 |
2021-05-01 | Abstract The question of the application of Poisson’s law PV γ = сonst in the analysis of spatiotemporal variations in the parameters of the neutral atmosphere in this region is considered in relation to the existence of heat fluxes in the mesosphere-lower thermosphere (MLT). Poisson’s law is valid for adiabatic processes, i.e., in the absence of heat transfer (Δ Q = 0). When internal gravitational waves propagate in this region, which, when dissipated, transfer energy and angular momentum to the medium and can enhance turbulent motions, as well as during the development of the frequently observed dynamic and convective instabilities, the processes in MLT can also be nonadiabatic. In this study, we obtained the values of the n index in the lower thermosphere for polytropic processes PV n = const, when only the heat capacity is constant. To estimate the n index, we use measurements of the temperature and density of the neutral atmosphere by the method of resonant scattering on artificial periodic irregularities of the ionospheric plasma. It is shown that above the turbopause, the polytropic index n lies in the range of 1.8 to 2. The fact that n > γ indicates the importance of taking the heat transfer in the lower thermosphere into account. | Polytropic Processes in the Lower Thermosphere | 10.1134/S199079312103012X |
2021-05-01 | The boundary conditions for describing the mass transfer of carbon from a low-pressure oxygen-free atmosphere into steel under vacuum carburizing are analyzed. Experimental results and thermodynamic calculations are used to determine the numerical value of the activity of carbon in an environment of low-pressure acetylene. The calculated value of the carbon potential is used in the boundary condition of kind III in the form of a Langmuir expression applied to a mathematical model of vacuum carburizing based on numerical solution of the diffusion equation. The calculated concentration profiles are shown to describe adequately the experimental results. Different nonequilibrium processes of vacuum carburizing of steels are shown to have similarity. | Problems of Simulation of Carbon Mass Transfer from Low-Pressure Saturating Atmosphere into Steel | 10.1007/s11041-021-00654-0 |
2021-05-01 | Abstract Results of laboratory and industrial investigations of the secondary steelmaking of structural steel by binary and multicomponent alloys based on silicon with alkaline earth metals (AEMs) show a decrease in the microheterogeneity of liquid metal, contamination with nonmetallic inclusions (NIs), formation of fine oxysulfide NIs, and production of more uniform and dispersed structure of steel. The compound alloys with strontium, which provide high cold resistance and corrosion resistance of steel, are considered most effective. | Secondary Steelmaking with Compound Alloys with AEMs—an Economically Feasible Approach to Improve Steel Quality | 10.3103/S0967091221050107 |
2021-05-01 | Photosynthetic rates vary depending on growth conditions, even within species. Remote sensing techniques have a great potential to predict the photosynthetic rates of leaves with different characteristics. Here, we demonstrate that the photosynthetic rates of leaves acclimated to different light and nutrient conditions can be estimated based on the chlorophyll fluorescence (ChlF), the photochemical reflectance index (PRI), and a chlorophyll index. Chenopodium album plants were grown under different light and nutrient conditions. PRI, ChlF parameters, and CO 2 /H 2 O gas exchange rates of leaves were simultaneously determined under the various light and CO 2 conditions. PRI was used to assess non-photochemical quenching (NPQ), but the relationship between NPQ and PRI was weakened when the data on leaves grown under different conditions were pooled, because PRI in darkness ( $$\text {PRI}_0$$ PRI 0 ) changed with the leaf pigment composition. Among 15 pigment indices, we found that $$\text {NDVI}_\text {green}$$ NDVI green , a reflectance index related to the leaf chlorophyll content, had the best correlation with $$\text {PRI}_0$$ PRI 0 ( $$r^2=0.89$$ r 2 = 0.89 ) across the studied leaves, and the correction of PRI by $$\text {NDVI}_\text {green}$$ NDVI green improved the predictability of NPQ ( $$r^2=0.82$$ r 2 = 0.82 ). Using the steady-state ChlF, the NPQ estimated from PRI and $$\text {NDVI}_\text {green}$$ NDVI green , and the stomatal conductance coefficient, we calculated the CO 2 assimilation rates, which were strongly correlated with the actual rates (RMSE = 4.85 $$\mu$$ μ mol m $$^{-2}$$ - 2 s $$^{-1}$$ - 1 ), irrespective of growth conditions. Our approach has the potential to contribute to a more accurate estimation of photosynthetic rates in remote sensing. However, further studies on species variations and connecting with radiative transfer models are needed to demonstrate this at the canopy scale. | Estimating leaf photosynthesis of C3 plants grown under different environments from pigment index, photochemical reflectance index, and chlorophyll fluorescence | 10.1007/s11120-021-00833-3 |
2021-05-01 | The vacuum-arc plasma-assisted method is used to deposit a multilayer coating based on Ti and Al in two discharge systems – in a traditional plasma-assisted vacuum-arc spraying system and in a gas-metal beam-plasma generation system in a hollow cathode of a non-self-sustained low pressure glow discharge. The coatings synthesized in these discharge schemes have close elemental and phase compositions. The aluminum content in the coating deposited in the plasma-beam formation is 8% lower, which is probably due to a higher overall average value of the ion flux density on the surface of the growing film in a non-self-sustained glow discharge. In the coating deposited by sputtering in a beam-plasma formation, no elements are part of the material of the sputtered hollow cathode. The gas-metal beam-plasma formations generated at low pressure are promising in the processes of functional coating deposition by the vacuum-arc plasma-assisted method. | Deposition of a Multilayer Coating in a Gas-Metal Beam-Plasma Formation at Low Pressure | 10.1007/s11182-021-02310-9 |
2021-05-01 | During the highway construction along the Yangtze River in Anhui, China from 2015 to 2018, regional slope failures occurred frequently near the routes and constituted significant hazards to infrastructures. Especially from June to September in 2016 and 2017, the high-temperature weather and intensive rainfall hit this region, triggering a lot of slope failures. These slope failures have two puzzling features: (1) low height (2.5–5 m) or gentle dip angles (8–25°). Such height and dips are unlikely to fail in theory; (2) slope failure emerged immediately during rainfall, while the slope materials consist of clay soil with extremely low permeability. Field investigations, laboratory tests, and a large-scale slope model test were conducted to investigate the failure modes and mechanism of the slope failures. The results show (1) low steep slopes generally show failure modes of surface erosion, or repeated local failures around the slope shoulder, while the gentle slopes often display failure modes of overall failure or even landslides; (2) the slope material mainly contains clay mineral of illite and displays strong shrinkage ability, which is prone to forming desiccation cracks during drying evaporation. Desiccation cracks can significantly improve the infiltration capacity of soils with three or four orders of magnitude. Shear strength of the soil is sensitive to water and decreases sharply with the increased water content; (3) the large-scale slope model test confirms that desiccation cracks can induce slope failure by providing preferential flow pathways for rainwater to rapidly infiltrate into deep soils. Based on the above results, the difference of failure modes and scales between the steep slope and gentle slope is interpreted. It is inferred that desiccation cracks are difficult to develop stably and constantly on the inclined surface of steep slopes due to the intense surface runoff. Thus, surface erosion and shallow flow-slip dominate the failure modes of the low steep slopes. Conversely, a gentle slope surface is favorable for the development of desiccation cracks. Hence, overall slope instability or a landslide is more likely to occur in a gentle slope after long periods of drying-wetting cycles. | Research on the rainfall-induced regional slope failures along the Yangtze River of Anhui, China | 10.1007/s10346-021-01623-7 |
2021-05-01 | The atmospheric exposure test of low-hydrogen-embrittlement Cd-Ti plated (LHE Cd-Ti) 300M steel coupled with TC4 titanium alloy of different surfaces was conducted in Qingdao industrial-marine atmospheric environment. The corrosion behavior and mechanism of LHE Cd-Ti 300M steel in the galvanic couples were investigated by means of morphology observation, corrosion product analysis, electrochemical measurement and mechanical property tests. The results show that the composite coating of epoxy polyamide primer and acrylic polyurethane topcoat on the surface of TC4 titanium alloy can significantly reduce the galvanic corrosion behavior of LHE Cd-Ti 300M steel and TC4 titanium alloy, and delay the corrosion process of anode LHE Cd-Ti 300M steel, thus reducing the loss of its mechanical properties. The corrosion of LHE 300M steel in the industrial marine atmosphere of Qingdao is induced by pitting corrosion. After Cd-Ti coating layer gradually dissolves, the corrosive medium reaches the substrate-plating layer interface, and the generated corrosion products accumulate and overflow the surface. The Cl - in Qingdao atmospheric environment severely destructs the surface oxide film, which induces pitting corrosion. In addition, the corrosive media containing sulfate ions can directly participate in the reaction and further aggravate the corrosion. | Galvanic Corrosion of Low-Hydrogen-Embrittlement Cd-Ti 300M Steel Coupled with Composite-Coated TC4 Titanium Alloy in an Industrial-Marine Atmospheric Environment | 10.1007/s11665-021-05698-0 |
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